Supporting Emergent Knowledge andTeam Communication in Police Investigations

Claus Atzenbeck and David L. HicksAalborg University

Esbjerg Institute of TechnologyNiels Bohrs Vej 8, 6700 Esbjerg, Denmark

{atzenbeck, hicks}@cs.aaue.dk

Nasrullah MemonUniversity of Southern Denmark

The Maersk Mc-Kinney Moller InstituteCampusvej 55, 5230 Odense M, Denmark

memon@mmmi.sdu.dk

Abstract—This paper focuses on police investigations con-ducted by small teams of officers as they usually work onsolving violent crimes. Collaboration and communication areimportant aspects as well as connecting pieces of informationthat become known to the officers over time. This is an importantapplication domain of knowledge management, and in particularhypertext. We present a prototypic application, Socs, that permitsthe intuitive connecting of information on a space. It supportsemergent and dynamic knowledge structures, fosters commu-nication, awareness and notification services, enables multipletrails of thought in parallel (i. e., thought experiments), as wellas versioning with easy access to previous states. As a comple-ment to the database and network analysis driven applicationsavailable today, we propose a tool for criminal profiling or crimescene analysis supporting small teams of officers in knowledgestructuring and collaboration.

Index Terms—police investigations, crime scene analysis, com-munication, collaboration, emergent knowledge, versioning, Socs

I. INTRODUCTION

Police investigations include a variety of tasks. An importantone is criminal profiling. There have been individual attemptsat creating profiles before 1970 [1], [2]. A prominent exampleis the profile of Jack the Ripper in 1888. In the 1970sthe FBI (“Federal Bureau of Investigation”, USA) foundedthe Behavioral Science Unit (BSU) which became the firstorganization for systematically creating offender profiles. Theyintroduced crime scene analysis [3]. The first documentedsystematically generated profile in the US was created in 1974.In the 1980s profiling became adopted in Europe, includingGermany, Switzerland, [1] and Russia [2]. Various otherdisciplines became involved, such as investigative psychologyin the UK in the mid 1980s [2] and later in Austria [1].

Electronic data processing became an important tool incriminal investigations. For example, in the mid 1980s thedatabase VICAP (“Violent Criminal Apprehension Program”)was introduced in the US. It supports officers in finding linksbetween different crimes. In the late 1980s a similar database,ViCLAS (“Violent Crime Linkage Analysis System”), becamethe de facto standard for classifying serial crimes in manycountries.

Besides various databases and other specialized applica-tions, paper is still an important medium for storing andsharing information related to criminal investigations. Hetero-geneous and incompatible sources, however, cause problems

for accessing or sharing information. In addition, officersspend a large portion of their time involved in communicationtasks during the course of an investigation. Referring to [4],Zhao et al. points out that “[i]t is estimated that police officersspend up to 40 % of their time handling information, makingit one of the most extensive police activities” [5]. This has twoconsequences: (1) due to problems caused by heterogeneousmedia use it is hard to make connections between informationitems, thus sharing becomes difficult; (2) much of the commu-nicated information does not become part of the knowledgerepository and thus becomes inaccessible to others or becomesforgotten over time. The lack of sharing information has alsobeen recognized as one of the problems that made the 9/11terrorist attack possible [6].

Most information produced by police officers is difficult torepresent and thus to access or communicate due to its nature.“Police knowledge tends to be implicit, tacit, and based onexperience” [7]. Most computer systems used by the police,however, “are based on a classification mechanism using legaldefinitions of crimes” [8]. This leads to problems in capturing,using, organizing, and distributing/sharing tacit knowledge.Another type of application is needed that can overcome theweaknesses caused by formal representation required by mostexisting tools, and that permits the iterative development ofinformation [9].

Another aspect of police investigations is the frequent statuschanges based on newly entered information from differentsources, including those based on the officers’ experience (tacitknowledge) [9]. However, relations between a new piece ofinformation and existing ones may not be obvious upfront,they may change frequently, or may have various and changingdegrees (i. e., strength). This emergent nature of knowledgestructures is hard to capture intuitively with graph-based ordatabase-like applications.

Spatially represented knowledge structures address many ofthe above mentioned problems. They permit the informal andintuitive association of information in a visual manner that ismore appropriate for representing and communicating tacit andemerging knowledge. So-called spatial hypertext applicationsare typical examples of applications in this area. They weredeveloped by hypertext researchers who observed in the early1990s that the typical node–link paradigm does not provide

978-1-4244-4173-0/09/$25.00 ©2009 IEEE 95 ISI 2009, June 8-11, 2009, Richardson, TX, USA

good support for emergent knowledge structures. Frank Halaszpointed this out in his 1991 Hypertext Conference keynoteby demanding the “Ending the Tyranny of the Link” [10]and proposing so-called “supra-network hypertexts”, that arehypertexts other than those based on networks.

There are several examples of spatial hypertext applications,such as Aquanet [11], VIKI [12], Visual Knowledge Builder(VKB) [13], Tinderbox [14], and WildDocs [15], [16]. Thosesystems are based on a cards-on-table metaphor. Similar tocards on a table, the user can associate pieces of informationthrough spatial proximity or visual cues, such as color, shape,or size.

Research has shown that the less formalized way of express-ing knowledge in spatial hypertext systems has major advan-tages, especially for collaborative environments: “Users arehesitant about formalization because of a fear of prematurelycommitting to a specific perspective on their tasks; this maybe especially true in a collaborative setting, where people mustagree on an appropriate formalism and the conventions for en-coding information into them” [17]. Thus, spatial hypertext ismore appropriate and beneficial for expressing tacit knowledgethan most existing applications used for police investigations.

Furthermore, due to its visual nature, spatial hypertextcan provide an overview of information provided by variousdata sources and can act as a means for notification andawareness services, as we have argued in previous publications[18], [19]. In our recent work we have further proposed aspatial hypertext prototype that provides the means to storeand navigate through multiple versions of knowledge [20].This becomes important when, for example, the status of aninvestigation needs to be explained to new team members. Inmany cases showing the development of knowledge can helpto discover and communicate tacit knowledge that otherwisewould be hidden. This may include references “to previousitems or experiences” [21].

In this paper we propose the use of a specialized spatialhypertext application that integrates various other informationsources. It provides an intuitive interface to express emer-gent knowledge and its development over time and aims atstimulating officers to store as much as possible of their tacitknowledge related to a case such that it does not get lost,becomes easily accessible to other officers, and is available tothe system for notification and awareness services. In Sect. IIwe give a short overview of various types of systems used forpolice investigations and position our approach among them.Section III presents some methods used for criminal analysisand points out some shortcomings of the currently used ITsystems. Section IV provides an overview of our currentprototype and discusses its potential for supporting policeinvestigations in addition to the existing systems. Finally,Sect. V concludes the paper and provides a brief look at futureresearch.

II. IT FOR POLICE INVESTIGATIONS

As mentioned in the introduction, many IT systems usedas tools for police investigations are for managing large

amounts of data. This is an application domain of databases.There are a variety of different criminal information databasesand “[i]n many local law enforcement agencies, . . . [they]exist as isolated stand-alone systems” [22]. Examples includeHOLMES (“Home Office Large Major Enquiry System”, UK),CATCHEM (“Central Analytical Team Collating HomicideExpertise and Management”, UK), HITS (“Homicide Inves-tigation Tracking System”, USA), and HEAT (“HomicideEvaluation and Assessment Tracking”, USA) [3].

Another more prominent example is VICAP (“ViolentCriminal Apprehension Program”), a database introduced inthe USA on a national level [3]. It captures information onhomicides and homicide attempts without obvious motivesand sex crimes, missing persons indicating a criminal act, andunidentifiable bodies of people who were likely or certainlykilled. VICAP uses a “Crime Analysis Report”, that is aquestionnaire of 189 questions describing a crime. Crimeelements can be differently weighted. For instance, the waylimbs of two bodies are cut off may be stronger weighted thana similar weapon being used in a crime [3]. However, VICAPturned out to be less than user friendly, thus its acceptancehas been low. Because it is the decision of the police stationwhether or not to add a crime to the database, it is estimatedthat only 10 % of murders in the USA are tracked this way.

VICAP’s reduced acceptance lead to the development ofa similar system in Canada, called ViCLAS (“Violent CrimeLinkage Analysis System”) [3]. Its aim is to identify serialcrimes. It is compatible with VICAP, but also more userfriendly. In addition to those crimes types tracked by VICAP,ViCLAS also holds other sex crimes (e. g., rapes) and kid-nappings. It is based on a catalog of 168 questions, mostof which are multiple choice types. ViCLAS is availableto police authorities in other countries and became the defacto standard for classifying serial crimes in many of them,including Austria, Germany, Great Britain, Belgium, Australia,and Switzerland [3], [1]. Furthermore, unlike with VICAP inthe USA, there is a mandatory obligation to register crimeswith ViCLAS in some of those countries (e. g., Canada andGermany).

In most existing databases used by police officers, searchesmust be conducted manually [3]. However, some systems doinclude advanced analysis or intelligence services. Examplesinclude, in addition to the above mentioned databases VICAPand ViCLAS, i2, SPS (“Suspect prioritization system”), Wat-son, [23] and COPLINK [24]. Many of those applicationsimplement visualization tools that represent aspects of thestored data to the officers.

Furthermore, there have been various other systems usedfor police investigations, such as expert systems (e. g., “Devonand Cornwall constabulary expert system” or “Ottawa policeservice” [23]) and classification systems (e. g., “Clevelandconstabulary” [23] or HOLMES [2]). Geographic informationsystems (GIS) have also been used such as CGT (“CriminalGeographic Targeting”) and combined with statistical methods,such as is done in ReCAP (“Regional Crime Analysis Project”)[23].

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Most specialized systems presented in the literature focus onstoring or analyzing crime-related information. There is littleinformation provided on systems that support collaborationin police investigations. One exception is COPLINK that “di-rectly targets the problems of information sharing and criminalanalyses within and between law enforcement agencies” [24].

Even though some of the applications described aboveare efficient tools for the information gathering and sharingprocesses, they provide only minimal support for construct-ing, representing, and communicating tacit knowledge, asit appears in meetings or conversations among members ofsmall investigation teams. In order to illustrate the benefitsof very specialized association and communication tools fortacit knowledge, we next examine selected crime investigationmethods and their associated requirements.

III. INVESTIGATORS’ WORK

In this section we point out some requirements necessaryto support police investigations, especially those related toviolent crimes or hijacking. We use this discussion as a basisto propose special tools supporting the knowledge creation andcommunication processes.

Police investigations can be described in various ways. Forexample, Hoffman & Musolff [3] divide them into two phases,the first one including the following steps:

1) Textualization: textualizing traces, evidences, testi-monies, that are connected to the crime.

2) Thought experiments: finding competing possible textsequences.

3) Stepwise developing thought experiments, including ver-ification according to collected information about crimescene or crime time.

4) Differentiating between a primary crime act and possiblesecondary crime camouflage.

5) Identifying casual facts (very important for interpreta-tion).

6) Creating chronological and logical reconstructions of thecrime based on the developed text, including consequen-tial hypotheses and speculations.

7) Logging the results of the analysis (should be conciseand helpful even for people not having seen the crimescene).

In phase two officers structure the collected data accordingto search hypotheses or try to match it with concrete suspects.Our focus is mostly on the first few work tasks in phase oneas well as the documentation aspect in step 7.

With the initial work in phase one, that is textualization,officers create textual fragments that need to be structured inlater steps. Thus, a tool supporting this step must provide themeans to create piles of primarily unsorted and unconnectedinformational units.

Furthermore, textualization is the basis for team work pro-viding a medium for communication. Team work has variousadvantages related to collective knowledge, including synergyeffects, a larger number of and more objective hypotheses, etc.Based on these advantages, crime scene analyses performed

by the German BKA (“Bundeskriminalamt”, i. e., “GermanFederal Criminal Office”) are conducted in teams as a matterof principle [25]. This raises the need for a system to supportcollaboration in small groups.

The subsequent work steps, that are developing and adjust-ing thoughts experiments, aim at structuring the provided textfragments such that hidden information gets revealed. Thistask poses the following challenges:

1) The final structure is unknown until the end.2) The intermediate structure gets changed frequently due

to new information being considered (i. e., the structureis dynamic).

3) Connections between various informational units maynot be obvious at the beginning but may be revealedcasually.

4) Alternative structures may exist (“thought experiments”)in parallel.

5) The evolution of the structure may contain importantinformation about the officers’ line of reasoning.

6) Different structure types must be supported.A tool supporting the collaborative authoring of dynamic

structures must provide the means to easily and quicklyassociate or disjoin information. A versioning-like mecha-nism should support the development of different versions,and notification services should inform users about implicitconnections between different versions. Intuitive interactionregarding traversing through the structure’s previous statesand to continue working from any of them is important.Furthermore, the tool must be capable of providing variousviews of the crime represented with different structure types,including a chronological sequence, a spatial (e. g., crimescene) view, sociological view (e. g., personal connections),taxonomic perspective, etc. In order to avoid redundancy,identical elements should be reused in the various versions.

The intermediate states as well as the result of the analysis(step 7) must be easy to communicate to others who are notfamiliar with the crime. A sequential text has the disadvantagethat it must be perceived in a linear fashion. Consequentlyits use might require a considerable time for the user toget a sufficient overview of a subject. In contrast, visualpresentation of information can be processed in parallel and ismore efficient in providing an overview. Thus, a tool shouldgo beyond textual representation and also use visual elementsto exploit the human capability to parse visual structures morequickly.

Our brief analysis applies to other work tasks that have simi-lar characteristics as the ones described. These include those inwhich a team works with originally unstructured informationthat needs to be interpreted and associated in a number ofdifferent different views. This is true for many investigationmethods, corresponding to the different approaches utilized invarious countries. For instance, the main focus of the AmericanFBI is on the offender’s personality (called “offender profiling”in the US or “behavioural analysis” in the UK [26]) whereasthe German BKA emphasizes mainly the situational factors ofthe crime (i. e., crime scene analysis) [3], [2].

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Various other profiling methods are also used, such asgeographical profiling (analysis of an offender’s spatial be-havior) [27], [28], psychological, empirical, and mathematicalprofiling [1], [2]. Profiling is either done collaboratively oras an initial phase, after which the results are provided toand used as input for teams to be further evaluated and usedtogether with other sources.

IV. THE SOCS PROTOTYPE

As discussed in previous sections, most specialized toolsavailable for police investigations focus on managing andanalyzing large sets of data. Only a few are concerned withsupporting the important phases of investigation described inthe previous section.

We observe that many of the problems faced by law enforce-ment are very similar to those encountered by business firms[22]. Considerable research has been done in the knowledgemanagement field to address the needs of companies. Theseresearch results also have applicability in the law enforcementarea. Especially relevant for the particular challenges facedby criminal investigators are the research results from theknowledge management subfield of hypertext.

For decades hypertext has been recognized as a “computer-based medium for thinking and communication” [29]. Its sup-port for collaboration and associating originally independentpieces of information makes it a natural candidate for the tasksdiscussed in the previous Section. Furthermore, the hypertextcommunity has progressed beyond the node–link paradigm(as it is widely known from the WWW’s Web pages that areconnected through links) and introduced additional structuretypes, including spatial hypertext [12], taxonomic hypertext[30], and argumentation support structures [31]. This permitsa selection of the structure type that is best fit to and mostappropriate for the task at hand.

We developed a prototype called Socs (currently in an earlydevelopment phase) that features a space on which informationcan be associated. It is a so-called spatial hypertext applicationthat represents associations implicitly through spatial distance,alignment, or visual cues, such as color, shape, or size. Itfollows a cards-on-table metaphor. As with cards on a table,objects on a virtual space can be moved. When this is donetheir associations change accordingly.

As pointed out in [32], the relevance of spatial hypertextfor collaborative analysis tasks was also recognized by theCIA’s Office of Research and Development (ORD) by fundingits early development of systems providing this capability,including the first spatial hypertext applications Aquanet [11]and VIKI [12], as well as one of their earlier relatives,NoteCards [33].∗

Whereas traditional hypertext (i. e., node–link structures) arehighly formalized, spatial hypertext lacks such explicit connec-tions. Such structures are dynamic and ambiguous by nature.

∗According to an e-mail conversation with Cathy Marshall on 2008-06-03.Even though internal reports were written, there is no publication known to usthat discusses the use of these applications in the concrete case of intelligenceanalysis at the CIA.

They may change significantly while moving objects and alsomay suggest several (possibly contradicting) interpretations.The ability to quickly adapt to newly added information andsupport multiple views increases creativity and may lead tooriginally unexpected insights.

It is the nature of investigations that the introduction ofnew evidence requires to verification and adaptation of parts ofthe existing structure. New, originally not obvious connectionsmay become revealed casually. Spatial hypertext’s ability tosupport this in a user-friendly and intuitive way matcheschallenges 1, 2, and 3 described in the previous Section. Fur-thermore, spatial hypermedia may reduce the cognitive coststhat are inherent with document-centric node–link structuresfor identifying and defining links (since originally there arenone) and the reorientation of the user after traversing a linkand arriving at the destination node, which may require up toseveral seconds [34, p. 376].

Another important aspect especially in collaborative work-ing environments is that “[u]sers are hesitant about formal-ization because of a fear of prematurely committing to aspecific perspective on their tasks; this may be especiallytrue in a collaborative setting, where people must agree onan appropriate formalism and the conventions for encodinginformation into them” [17]. Shipman et al. argue that “[u]singnode and link hypertext to express an emerging or evolvingunderstanding means structuring and restructuring the materialover time. This overhead makes traditional hypertexts ill-suitedto many types of analysis and design tasks – particularly,situations where a lot of information must be interpretedrapidly or where a group shares and restructures informationin order to coordinate or reach consensus.” [13]

As mentioned previously, one task during the investigationis to generate thought experiments based on the existinginformation (step 3). The team aims at finding the missingconnections for reconstructing the crime. This creates multipledifferent trails of thought that must be represented, visualized,and made navigable by the application. Each trail creates itsown version. We have designed sophisticated mechanisms inthe Socs prototype for both authoring and navigating differentversions [20].

Being aware of how and why the currently displayedknowledge structure state has been reached is important forpolice investigators, especially if several parallel threads (i. e.,thought experiments) exist. For example, some information onthe space may become isolated from their original context overtime and may not be clearly understood anymore. Browsingback in time and observing the development of the structureover time would then reveal the original semantics. (See [35]for a real use case.)

Information about how the space developed over time couldbe noted on external sources, such as annotations that describethe steps performed [35]. However, this takes additional effortand is not practical in general. Instead, we propose a navi-gation mechanism to browse through Socs’ version structuresuch that any state can be easily displayed and revisited. Thestructure evolution over time can reveal connections that may

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have been lost otherwise. Furthermore, the officers may beginmodeling thought experiments directly from any displayedstate. Providing a user friendly version control mechanism thusenables representation of knowledge in a way that addressesrequirements 4 and 5 described above.

Keeping track of various versions generated by a teamof several people produces lots of knowledge that exists inparallel. Browsing previous states and thus observing theevolution of the knowledge space is possible. However, officersmay not necessarily be aware of connections between twoparallel states that were possibly even created at differenttimes. For example, a knowledge structure (i. e., informationalunits that are implicitly connected through spatial proximityor similar visual cues) similar to one currently displayed mayhave been created by a team member a long time ago andbeen forgotten. If Socs was aware of the similarity betweenthe knowledge structures, it could notify the officers who thencould go back to the respective state and analyze the formercontext and circumstances. This may reveal some relevantinformation that became lost over time and that is no longerbeing considered in the current state.

We discussed awareness and notification issues in the con-text of wikis [18], that are Web-based services for collaborativewriting. In order to support this kind of awareness, we proposea so-called spatial parser [36] that is capable of interpretingthe spatial structure and representing implicit associationsexplicitly. This enables – in addition to notification services –search queries that consider the objects’ contexts.

Furthermore, as discussed in [18], Socs connects to variousother data sources that are considered for notifications. Forexample, it would recognize if people who co-authored a cer-tain wiki page also exist on the space. This becomes importantfor police investigations, because there are many external datasources. Contrary to projects like COPLINK Connect [22] thataccesses a set of relevant databases to permit searching forpersons, vehicles, incidents, and locations, Socs additionallyis meant to connect to productivity tools used frequently byofficers, including e-mail, Web browsers, document viewers,and text processing applications. This enables notificationsabout occurrences of subjects, events, or other issues thatappear in currently viewed documents that are also part ofthe structure provided by Socs. Furthermore, Socs acts asa medium for connecting information from those sourcesdespite their application boundaries. This overcomes partly theproblem of islands of data that cannot be associated or linked,as was identified twenty years ago [37].

Socs shares concepts found in other investigation tools,such as i2 Analyst’s Notebook [38] or COPLINK [24]. It’smain conceptual contributions as discussed above can besummarized as: (1) supporting the collaborative organizationof unstructured and incomplete information through the useof informal structures, (2) providing time representation andversioning, and (3) overcoming issues that occur with hetero-geneous data sources by integrating officers’ frequently usedproductivity tools and providing inter-application associationsand notification services.

V. CONCLUSION AND FUTURE WORK

In this paper we examined challenges for police inves-tigations, many of them related to the collaboration andcommunication needs of small teams. The emergent nature anduncertainty of the information snippets that are collected overthe duration of an investigation and the importance of thoughtexperiments and documentation generate special requirementsfor support applications. We argue that most existing appli-cations used in this field focus on gathering and analyzinglarge sets of data, but do not support or foster collaborativethinking processes. They exhibit shortcomings in the handlingof incomplete information or changing interpretations and thusare not an appropriate means for humans to express theirthoughts or experiences (tacit knowledge). As a result, muchof this work is still done on paper, despite its disadvantagesregarding sharing, ease of access, and machine processing.This is noted more generally in the literature: “Unlike thepopular view propagated by the television and film industries,law enforcement agencies are anything but cutting-edge intheir use of information technologies for information sharingand criminal intelligence analyses.” [22]

Solutions for the described problem can be found in theknowledge management area and – more specifically – inthe field of hypertext. We propose a spatial hypertext toolas a compliment to existing information systems to providea means for officers or teams of officers to represent andcommunicate their thinking and personal analyses. With thatwe aim at “augmenting human intellect” [39], a goal ofhypertext research since its very beginning.

Our application prototype, Socs, is a spatial hypertextapplication at an early development stage. Development ofthe system is ongoing to extend the prototype to include theentire set of capabilities discussed in the previous Section.In other publications we have discussed its use for collab-oration [18] and versioning support [20]. In this paper weapply the benefits of spatial hypertext to the identified needsfor police investigations. Our research on Socs first focusedon examining its potential regarding space, awareness, andtime representation (i. e., versioning). It currently focuses onsocial relationships, that is, organizing people on the spaceand receiving information about their involvement in externaldocuments (currently wiki authorships). However, once Socs’capabilities in representing various types of data are extended,officers could add various other documents to the knowledgespace and organize them accordingly, including office docu-ments, multimedia data, events, or actions.

Currently Socs is a pure spatial structure application, how-ever, as discussed above (challenge 6), other structure typesmay be of importance. Hypertext research became liberatedfrom exclusively supporting node–link structures and hasseen the development of application environments that canhandle arbitrary structure types that run in parallel using thesame infrastructure. Examples of these environments, knownas component-based open hypermedia systems (CB-OHS) orstructural computing environments (SC) include Callimachus

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[40] or Construct [41]. In a future version of our prototype weplan for Socs to be implemented as a CB-OHS or SC servicesuch that it can easily interoperate with other structure types,such as with taxonomic or argumentation threads.

Neither machines nor data sets alone can reach a finalsolution or decision regarding a police investigation. It isthe police officers that evaluate various sources and reflectupon them. Although databases and analysis applications canprovide additional useful information, they lack sophisticatedsupport for the critically important tasks of supporting policeofficers’ thinking and communication processes. Providingtools that augment police officers’ thinking and that make useof their experience and tacit knowledge may draw unexpectedbenefits for police investigations.

ACKNOWLEDGEMENTS

We acknowledge Fatih Ozgul for his valuable comments.

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