Developing Investigative Linguistics as a Forensic Science

Dr Tim GrantDeputy Director,

Centre for Forensic [email protected]

Developing investigative linguistics as a forensic science.

Forensic Linguistics & Investigative Linguistics

Study of legal textsstatutes, contracts, wills etc..

Study of legal linguistics processesE.g. Police interviewing

• The question of question types in police interviews.– Oxburgh, Myklebust & Grant (In press July 2010)

Provision of linguistic evidenceTrademark disputesJudging Linguistic CompetenceFailures in Interpretation e.g. in police interviewsInvestigative linguistics: the investigation of forensically interesting texts to aid investigation and or provide evidence.

Historical Development Timothy Evans

1950 - hanged for the murder of his wife and child.

1968 - Jan Svartik analysed Evan’s witness statement and suggested the language was inconsistent. A case for forensic linguistics.

Derek Bentley 1953 – hanged for his part in the murder of a policeman.

1998 – Court of Appeal set aside the conviction in part because of Malcolm Coulthard’s evidence that his statement was not “verbatim record of spoken monologue” as claimed at the original trial.

Dhiren Barot

2004 –charged with terrorist offences on the basis of linguistic evidence indicating that he had written conspiracy documents including the Gas Limo Project.2006 – sentenced to 30 years imprisonment after pleading guilty.

Development of confidence & standards of proofIn the UK…

Intelligence or investigative assistance or expert advice.Casting doubt.Balance of probabilities.

Being more certain than otherwise.

Beyond reasonable doubt Being certain.

Intelligence Casting Doubt

Balance of probabilitiesCertainty

BUT even when giving investigative adviceAny report may be subject to disclosure to the defence under UK law.This should not constrain giving opinion so long as you are explicit about your degree of (un)certainty. In practice what one is willing to say may depend upon the relationship with the police officer or client!

Sociolinguistic profilingWhat sort of person wrote this…

What sort of psychological person…?

What sort of linguistic person… ?

“She was an innocent girl who tried to do her best in a

world governed by old cruel farts. […] Sir, the whole system stinks. Sometimes, I am ashamed to be white by the things others are allowed to say and do. […] Surely, this cannot be right? […] Sir, it is time to bring these shameful things out into the open. Please. Do’nt let our country go down

the pan just to protect the interests of a few bad-minded people.”



Op. Heron 57 Letters Sent to a variety of recipients.Qualitative & statistical judgements feed in to profile:

Older writer• ‘hence’, ‘thrice’• ‘negroes’,

‘halfcaste’Woman

• ‘I’ underused.See BBC Crimewatch website for

more information:



http://www.bbc.co.uk/crimewatch/solved/forensicfiles/forensic_linguistics.shtml

Casting doubt

Doubtful witness statements – Courts of Appeal.Derek Bentley (Coulthard, 1994) – more in a moment…

More recent cases for Northern Ireland Police Ombudsman and the Criminal Cases Review Commission.

Responding to other experts’ forensic textual analyses.

Intelligence

Casting Doubt Balance of probabilities

Certainty

When acting for the defence the task can be to test and perhaps cast doubt on claims made for or about a text.

Derek Bentley statement

Bentley was hanged 28th January, 1953, for his part in the murder of a policeman.

On 30th July, 1998 he was pardoned, partly on the basis of the evidence of Malcolm Coulthard who demonstrated linguistic anomalies in his statement.

In the original trial it was claimed by the prosecution that the statement was produced by Bentley as a monologue and in response to a simple request for his account of events.

[…] The policeman then pushed me down the stairs and I did not see any more. I knew we were going to break into the place, I did not know what we were going to get - just anything that was going. I did not have a gun and I did not know Chris had one until he shot. I now know that the policeman in uniform is dead. I should have mentioned that after the plainclothes policeman got up the drainpipe and arrested me, another policeman in uniform followed and I heard someone call him 'Mac'. He was with us when the other policeman was killed.

Intelligence


Certainty

Derek Bentley statement

Intelligence


Certainty

‘then’ occurs 1 in 500 words in general language, 1 in every 930 words in undisputed witness statements, 1 in every 78 words in police witness statements and 1 in 57 words in this statement. ‘I then’ occurs 1 in 16500 words in general language, 1 in 5700 words in undisputed witness statements, 1 in 100 words in police witness statements 1 in every 190 words in this statement.

[…] My mother told me that they had called and I then ran after them. […] We all talked together and then Norman Parsley and Frank Fasey left. Chris Craig and I then caught a bus to Croyden. […] There was a little iron gate at the side. Chris then jumped and over I followed. Chris then climbed up the drainpipe to the roof and I followed. Up to then Chris had not said anything. We both got out on to the flat roof at the top. Then someone in the garden on the opposite side…

Civil process for dealing with incivility

Providing grounds for dismissal.Defense against claims of wrongful dismissal.Copyright infringement.Plagiarism detection.Disputes over drafting of informal wills

SURPRISE!!!FAT BEARDED TWAT

________________________________

YOU GOT THE WRONG MAN YOU GREAT FAT HAIRY BASTARD

YOU’RE A FAT HAIRY BASTARD + YOU PUSH PEOPLE TO FAR. WHY DON’T YOU JUT LEAVE. WE ALL HATE YOU.

YOU’RE A CRAP TEACHER AND YOU STINK. THE OTHER TEACHERS ALL LAUGH AT YOU. THE WAY YOU SLEARE

OVER THE WOMEN IN THE […] OFFICE IS A JOKE – WHO’D FANCY AN UGLY FUCKER LIKE YOU?

DO EVERYONE A FAVOUR + PISS OFF + KEEP YOUR NOSE OUT OF THINGS THAT DON’T CONCERN YOU

YOU’VE BEEN WARNED



Daubert criteria and new UK Law Commission review on expert evidence.

Daubert criteria for acceptability of expert evidence in US federal courts.

Has the theory been tested?

Has it been peer reviewed?

Is there a known error rate?

Is it generally accepted?

UK Law Commission on expert evidence heading in a similar direction.


Balance of probabilities

Certainty

Linguistic evidence in Operation Rhyme

Operation Rhyme – a counter-terrorism operation investigating Dhiren Barot (and others).

Chronology 2nd August 2004: Barot arrested. 12th August 2004t: 11am received call, by 3pm in NSY working on

texts. 13th August 2004: by 8pm we had to produce initial evidential report

(this had to be put to Barot in interview before charge). 16th August 2004: Barot charged. Follow up through to September 2006: further analyses in

support in which we examined further texts, attempted to establish base rates, and produced numerous further reports.



Certainty

Gas Limo Project– language featuresFormality - “Sportsmen when sustaining injuries such as sprains during competition tournaments commonly utilise these ‘Packs’.”

Repeated units of semantic similarity - this feature took several forms.bracketed form: “this substance is poisonous (toxic)” symbol followed by word: “+ plus”



Certainty

Scare quotes: “in rural ‘countryside’ areas”

High frequency use of slashes “/” : “doctors/nurses”

Inappropriate use of semi-colons – following “because” and before explanations: “because; it seems at an early stage…”

Evaluation of analysis in Op. RhymeNot ideal!Other than time, pressure etc… of initial

analysis there were a variety of problems these included the data:A small number of very short texts of known authorship

text within an insurance claim.text of job application letters.

One very substantial query texttherefore consistency of style within one anonymous text.Other unconventional query texts

But… the highly idiosyncratic style led to fairly strong judgements of likelihood.

Outcome:Analysis assisted charging decision.Further investigation produced substantial further evidence.Guilty plea led to 40 year sentence (reduced to 30 years on appeal).



Certainty

http://www.youtube.com/watch?v=aXK6GQqL_L8

Danielle Jones

• Last seen 18th June 2001.

• After her disappearance a series of text messages were sent from her phone.

• Linguistic analysis showed that the later messages were sent by her Uncle, Stuart Campbell.

• Campbell was convicted of Danielle’s murder 19th December 2002 in part because of the linguistic evidence.



Certainty

Jenny Nicholl

• Last seen 30th June 2005.

• After her disappearance a series of text messages were sent from her phone.

• Linguistic analysis showed that the later messages were sent by her ex-lover, David Hodgson.

Hodgson was convicted of Jenny’s murder 19th February 2008 in part because of the linguistic evidence.

Text messages – audience texts

Author AHey, both! - but soph wont make it 4 dinner, she has a late lecture, prob b bk about half 8? She called but i cant get hold of her so i hope thats stil the plan xThanks my bro! i'll c you at xmas- so far away! Take care 2 xx

Author BYeah that sounds good. Is it the 25th thats her actual birthday?Hey chick, did you have a good weekend? I went to watch dave go kart rancing last night which was super fun as you can imagine!I can't wait to go home, dave's downloaded the new adam sandler film for me to watch tonight. What you guys up to? Xxx

These authors demonstrate stylistic differences in their writing of text messages.

So who wrote this one?Thanx bella! - gonna go 2 the student bar at 9. My room is huge! This place is v lux. Have a gd night! xx



Certainty

SUSPECT TEXT MESSAGES

Thought u wer grassing me up.mite b in trub wiv me dad told mum i was lving didnt giv a shit.been2 kessick camping was great.ave2 go cya

Hi jen tell jak i am ok know ever 1s gona b mad tell them i am sorry.living in scotland wiv my boyfriend.shitting meself dads gona kill me mum dont give a shite.hope nik didnt grass me up.keeping phone of.tell dad car jumps out of gear and stalls put it back in auction.tell him i am sorry

Y do u h8 me i know mum does.told her i was goin.i aint cumin back and the pigs wont find me.i am happy living up here.every1 h8s me in rich only m8 i got is jak.txt u couple wks tell pigs i am nearly 20 aint cumin back they can shite off

She got me in this shit its her fault not mine get blame 4evrything.i am sorry ok just had 2 lve shes a bitch no food in and always searching me room eating me sweets.ave2 go ok i am very sorry x

JENNY NICHOLL HISTORIC MESSAGES

Sum black+pink k swiss shoes and all the other shit like socks.We r goin2the indian.Only16quid.What u doin x

Yeah shud b gud.i just have2get my finga out and do anotha tape.wil do it on sun.will seems keen2x

Shit is it.fuck icant2day ive allready booked2go bowling.cant realy pull out.wil go2shop and get her sumet soon.thanx4tdlin me x

No reason just seing what ur up2.want2go shopping on fri and2will`s on sun if ur up2it

Sorry im not out2nite havnt seen u 4a while aswel.ru free2moro at all x

No im out wiv jak sorry it took me so long ive had fone off coz havnt got much battery

Only just turned my fone.havnt lied bout anything.no it doesnt look good but ur obviously jst as judgmental than the rest.cu wen i cu&i hope its not soon

I havnt lied2u.anyway im off back2sleep

I know i waved at her we wer suppose2go at4but was a buffet on later on so waited.anyway he had a threesome it was great cu around

Im tierd of defending myself theres no point.bye

Happy bday!wil b round wiv ur pressent2moz sorry i cant make it2day.cu2moz xxx

MY/MYSELFSPELT AS

ME/MESELF

JENNY NICHOLL HISTORIC MESSAGES

Sum black+pink k swiss shoes and all the othershit like socks.We r goin2theindian.Only16quid.What u doin x

Yeah shud b gud.i just have2get my finga out and do anotha tape.wil do it on sun.will seems keen2x

Shit is it.fuck icant2day ive allready booked2gobowling.cant realy pull out.wil go2shop and get her sumet soon.thanx4tdlin me x

No reason just seing what ur up2.want2goshopping on fri and2will`s on sun if ur up2it

Sorry im not out2nite havnt seen u 4a while aswel.ru free2moro at all x

No im out wiv jak sorry it took me so long ive had fone off coz havnt got much battery

Only just turned my fone.havnt lied bout anything.no it doesnt look good but ur obviously jst as judgmental than the rest.cu wen i cu&i hope its not soon

I havnt lied2u.anyway im off back2sleep

I know i waved at her we wer suppose2go at4butwas a buffet on later on so waited.anyway he had a threesome it was great cu around

Im tierd of defending myself theres no point.bye

Happy bday!wil b round wiv ur pressent2mozsorry i cant make it2day.cu2moz xxx

SUSPECT TEXT MESSAGES

Thought u wer grassing me up.mite b in trub wiv me dad told mum i was lving didnt giv a shit.been2 kessick camping was great.ave2 go cya

Hi jen tell jak i am ok know ever 1s gona b mad tell them i am sorry.living in scotland wivmy boyfriend.shitting meself dads gona kill me mum dont give a shite.hope nik didntgrass me up.keeping phone of.tell dad car jumps out of gear and stalls put it back in auction.tell him i am sorry

Y do u h8 me i know mum does.told her i was goin.i aint cumin back and the pigs wont find me.i am happy living up here.every1 h8s me in rich only m8 i got is jak.txt u couple wks tell pigs i am nearly 20 aint cumin back they can shite off

She got me in this shit its her fault not mine get blame 4evrything.i am sorry ok just had 2 lve shes a bitch no food in and always searching me room eating me sweets.ave2 gook i am very sorry x

SUMMARY OF STYLE

DIFFERENCES

IM / I AM

AM NOT/I`M NOT / AINT

IVE / AVE

MY/MYSELF/ME/MESELF

OFF / OF

TO/2 - SPACE/ TO/2 + SPACE

CU /CYA

FONE / PHONE

SHIT / SHITE

Measuring similarity in sexual crimeAssault A Assault B Are these crimes similar?

Jaccard’s coefficient is useful but has A & B as no more similar then A & C.

Woodhams, Grant and Price (2007) developed new measure Δs to apply first to sexual crime. (based on Izsak & Price, 2001).

Assault C

Verbal abuse

Bladed weapon used

Penile vaginal penetration

Verbal abuse

Bladed weapon used

Digital vaginal penetration

Verbal abuse

Bladed weapon used

No penetration

Husband-wife murder case.

I analysed a total of 407 text messages.A set of 154 ‘features’ were identified.Every text message was scored as containing or not containing every one of these features. Using Jaccard and Δs we can measure degrees of similarity / stylistic distance between any two text messages.

Text'4get' for 'forget'

'thanx' for 'thanks'

4 with no trailing space.

2 with no trailing space.

wen fo when

'wiv for 'with'

use of comma

'jst' for 'just'

Got go fetch milly. Val cant cope w her x 0 0 0 0 0 0 0 0

Wen r u up 4a repeat performance? X x 0 0 1 0 1 0 0 0

Txt me, talkin with chris. X x 0 0 0 0 0 0 1 0

Suspect text are messages significantly different from wife’s and indistinguishable

from husband’s.

Is this Certainty? My answer is ‘No’

“Of this group x is most likely writer...”

“There will be a small group of individuals who write this way… x is one of them.”

Language is always subject to variation in choice and chance.Linguistic data will only add to the weight of evidence – it will never be wholly probative on its own.

Is this science?



Certainty

Coulthard, M., & Johnson, A. (2007). An introduction to forensic linguistics Language in evidence. Oxford: Routledge. The Journal Speech Language and the Law –

T.J.P.K.A. Forensic Linguistics

Recommended reading

and of course…

Oxburgh Myklebust & Grant (In press July 2010) The question of question types in police interviews: A review of the literature from a psychological and linguistic perspective. Speech, Language and Law.

ReferencesCoulthard, M. (2004). Author identification, idiolect and linguistic uniqueness. Applied Linguistics,

25(4), 431-447. Coulthard, M., (1994) On the use of corpora in the analysis of forensic texts, Forensic Linguistics:

The International Journal of Speech Language and the Law, 25-43. Grant, T. (2007). Quantifying evidence for forensic authorship analysis Speech Language and the

Law. The International Journal of Forensic Linguistics, 14(1).Grant, T.D. (2007) Approaching questions in forensic authorship analysis In J. Gibbons and M.

Teresa Turrell (eds). Dimensions of Forensic Linguistics. John Benjamins. Grant, T.D. (in Press) ‘Txt 4n6 - Idiolect free authorship analysis?’, in Coulthard, R.M. and Johnson, A. (eds) Handbook of Forensic Linguistics Routledge Izsak, C., & Price, A. R. G. (2001). Measuring beta-diversity using a taxonomic similarity index,

and its relation to spatial scale. Marine Ecology Progress Series, 215, 69-77.Oxburgh Myklebust & Grant (In press) The question of question types in police interviews: A

review of the literature from a psychological and linguistic perspective. Speech, Language and Law.

Svartvik, J. (1968). The Evans statements: a case for forensic linguistics. Gothenburg Studies in English, 20.

Woodhams, J., Grant, T., & Price, A. (2007). From marine ecology to crime analysis: Improving the detection of serial sexual offences using a taxonomic similarity measure. Journal

of Investigative Psychology and Offender Profiling, 4 (2).

Developing Investigative Linguistics as a Forensic Science

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