Lindbergh Kidnapping—

The Ladder LinkBY Donna J. Christensen

March arrived raw, bleak andblustery in New Jersey’s SourlandMountain region. Along with theinclement weather came tragedy,horror and pain.

Wednesday morning, March 2,1932, the headlines of the nation’snewspapers announced the news— L I N D Y ’ S B A B Y K I D -NAPPED. Early accounts weresketchy. Someone , us ing ahomemade ladder to gain access tothe second-story nursery window ofthe Lindbergh home near Hope-well, N. J., had stolen the 18-month-old son of Charles Augustusand Anne Morrow Lindbergh.

The crime of the century arousedpublic interest and concern to alevel unknown before. Within fiveweeks, the Lindbergh garage over-flowed with mail—38,000 letters ar-

rived offering sympathy, sugges-tions, prayers and assistance.

One letter was from ArthurKoehler, a 46-year-old xylotomistand chief wood technologist at theForest Products Laboratory inMadison, Wis. He wanted to helpand had specific training and abil-ities to offer. As he had for morethan 20 years, Koehler continuedhis work at the laboratory, pursuingresearch on the growth, cellularstructure and identification ofwood. Such was the knowledge heoffered to detect clues in the aban-doned ladder. No reply came.

Ten weeks passed. Hope anddespair vied with one another. Wasthe child alive or dead? Negotia-tions resulted in a $50,000 ransompayment, but still no child. Then,on May 12, the body was discov-

ered partially buried in the woodsjust a couple of miles from theLindbergh home.

Now there was nothing more any-one could do to gain the child’s safereturn. All that remained was thesearch for justice.

The mail of late May, 1932, deliv-ered slivers from the ladder toKoehler’s office for identification.Through his microscope Koehlerobserved anatomical features thatindicated four different woods wereused to build the ladder—Douglas-fir, ponderosa pine, birch and a typeof southern pine known as NorthCarolina pine. A good first step, butexamination of the entire laddercould supply further information.His report was mailed to the NewJersey state police. Again hewaited. Ten months passed.

In spite of intensive investiga-tions by several separate policeunits, no suspects were appre-hended. The quest for leads contin-ued. In March, 1933, Koehler wasasked to come to Trenton to studythe ladder. Finally, a year after thecrime, the opportunity arose to“have the ladder talk. ”

Koehler was right. The “woodenwitness” had several clues to offerto an expert who could analyze andinterpret them. All of wood technol-ogy’s tools, techniques and knowl-edge were put to work. Every di-mension for each of the 19 ladderparts was measured to the nearest1/100 inch. Oblique lighting was em-ployed to reveal features barely dis-cernible under ordinary light.Marks left by hand saw, hand plane,chisel and machine planer were allanalyzed and measured in minutedetail. Calculations were made todetermine sawkerf widths and nailsize and shape. Page upon page ofdata were accumulating. Wherewould it lead? What could it tellabout the builder?

The ladder was one of a kind,crudely constructed, but requiringsome degree of carpentry com-petence. It consisted of three sec-tions, each 6 feet 8 inches long.When stacked on top of each otherthey would fit into a car; whenjoined together they could easilyreach a second-story window. Nosigns of wear were visible; it hadbeen used for a single special pur-pose. Someone, somewhere, tookArthur Koehler shown in his laboratory at the U.S. Forest Products Laboratory in 1936.

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Donna J. Christensen isa botanist in the Center forWood Anatomy Researchat the Forest Products Lab-oratory in Madison, Wis.The wood research facilityi s m a i n t a i n e d b y t h e

U.S. Forest Service of the Department ofAgriculture in cooperation with the Univer-sity of Wisconsin.

some lumber, sawed, chiseled andplaned it into a tool for kidnapping,and then left it behind. A long, dif-ficult and at times seemingly hope-less search began to locate thesource of the boards and subse-quently the person who purchasedthem.

It could be determined that 10of the ponderosa pine rungs werecut from a single 1” x 6” board.Two of the six rails had been cutfrom a 1” x 4” x 14’ North Carolinapine board. Another of the rails wastrimmed down from a wider board.

Koehler set out by writing onMay 24, 1933, to 1,600 mills in theNorth Carolina pine region. In apage-long letter, accompanied bythree pages of description and dia-grams, he provided detailed infor-mation about dimensions, growthcharacteristics, grade and planermarks for the two bottom ladderrails from the North Carolina pineboard. Only planers having sixknives in the side heads and eightin the top and bottom heads, spin-ning at about 3300 r.p.m. and feed-ing lumber through at approx-imately 258 feet per minute couldhave dressed the board.

A set of peculiar, almost invisibleplaner marks along the edge of theboard provided the clue needed totrace the lumber. For six months,on foot and via the mails, Koehlerhad “dogged” the piece of woodthrough hundreds of mills and lum-beryards. Frustration, dead ends,stares of disbelief were encounteredweek after week. But now, finally,the search had narrowed, first tothe Dorn mill in McCormick, S. C.,and from there to the National Lum-ber and Millwork Co. in the Bronx,N.Y. The date was Nov. 29, 1933.

The itemized purchases recordshould include the ladder builder’sname. But it was not to be. Thecompany operated on a cash basis;

The ladder found at the scene of the Lindbergh kidnapping (upper) and disassembled (below) foreasy transport in a car.

there was no list of customers. Afterall that effort, yet another deadend. There was no choice now ex-cept to start all over trying to tracea different board from the ladder.

In the meantime, police wereplotting points where ransom mon-ey was being spent and were tight-

ening the net around a suspect’sneighborhood in the Bronx.Koehler had suggested to policethat they watch for certain itemsshould they locate a suspect. Anycarpentry tools, especially handplanes, saws, chisels and nails,might supply important evidence.

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Evidence shows that ladder rail number 16 was sawed off from the attic floorboard seen at theleft. The original saw cut extends a short way into the next board and sawdust found on the lathand plaster below shows that the sawing was done after the floor was laid. Cut nails taken fromthe attic floor and pushed through four holes found in the ladder rail fit exactly in four correspondingholes in the joists. Two of these nails are visible in the picture.

Also, locations where a boardseemed to be missing.

September, 1934—Bruno Rich-ard Hauptmann, a carpenter, is ar-rested and charged with kidnappingand murder. Within his house andgarage are found $14,000 of markedransom money and carpenter toolswith links to the ladder. Among thetools are these items:

Nine hand saws—two have 10teeth per inch and produce a sawcut 0.0035 inch wide. Either fitsexactly the scratch marks and re-cesses found on the ladder.

A 2%” wide hand plane. Theblade has acquired its own uniqueset of nicks and grooves which willtell their tale at the trial.

In a package are four 8-pennywire nails with a “P” imprinted onthe shank. Exactly the same kindof nail used to fasten the ladderparts together.

And, in the attic of the house,

part of a floorboard is missing.The date is Jan. 24, 1935; the

place is Flemington, N.J. It is the17th day of the trial of the Stateof New Jersey vs. Bruno RichardHauptmann. Arthur Koehler issworn in as a witness for the stateand sits in the witness chair. Severalminutes of debate and dispute con-cerning Koehler’s capacity to actas a “wood expert” initiate his testi-mony. Over the objection of thedefense attorney, Mr. Pope, thecourt rules that Koehler be per-mitted to present his expert opin-ions.

Rail 16 from the ladder and itsrelationship to a floor board fromHauptmann’s attic is the first evi-dence to be examined. Koehler de-clares they were originally part ofthe same board. Many factors con-tributed to this conclusion.

(1) Rail 16 was punctured by four,square, 8-penny, cut nail holes not

used to construct the ladder, Eventhough it was used lumber, therewere no signs of exposure to theweather and no rust around the nailholes. Four nails of the proper sizeand shape were inserted into theboard. It was taken to Hauptmann’sattic. The nails fit exactly—size,spacing, angle and depth—intofour corresponding holes in thejoists of the attic floor. A one-in - 10,000,000,000,000,000 chanceaccording to Koehler’s calcula-tions.

(2) With the nails in place the railboard was oriented exactly parallelto the other floorboards.

(3) A pile of sawdust on the lathand plaster between the joists indi-cated that part of a floorboard hadbeen cut off and removed.

(4) Both the ladder rail and floor-board are North Carolina pine.

(5) The knot pattern is the samein both boards.

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A dull hand plane, full of nicks, was found in Bruno Hauptmann’s garage after his apprehension.When Koehler used the plane on a piece of pine, a peculiar pattern of ridges left by the nicksexactly matched those found on the kidnapping ladder. Koehler demonstrated this fact by actuallyplaning wood in the courtroom.

FORESTS & PEOPLEFOURTH QUARTER, 1977

Mill planer marks helped to trace parts of the latter back to a single sawmill and from thereto a single shipment of lumber to a yard in the Bronx, New York City. Crucial clues in tracingThis Lumber were a series of almost microscopic groves or gouges near one edge of the lumber.

(6) The planer marks are orientedin the same direction.

(7) The flat surfaces of the twoboards, despite a 1 3/8” gap, displaythe two halves of the same grainpattern.

(8) And, the end grain of bothpieces match perfectly. The annualrings are identical in number pre-sent (12), curvature, width varia-tion, prominence and percent ofsummerwood.

Koehler’s testimony next con-centrates on the hand plane marksobserved on several parts of theladder. He takes the 2½” hand

plane found on a shelf above theworkbench in Hauptmann’s garage.Clamping a board in a vice attachedto the judge’s bench, Koehler de-monstrates why he is convinced itit this plane and no other that wasused to smooth the edges of severalrungs and rail 16 of the ladder.Removing the board, he makes apencil tracing of the pattern ofscratch marks produced by the dullblade. The comparison to marksfound on the ladder leave littledoubt that the same tool made bothsets.

Among other pieces of evidence

presented by the state were factsthat Hauptmann had worked at theNational Lumber and Millwork Co.in the Bronx on several occasionsand that he purchased about $9worth of lumber late in December,1931. That was approximately twomonths before the kidnapping andwithin a month of receiving a ship-ment from the Dorn mill.

Throughout the trial Hauptmanndeclared himself both innocent ofthe crime and ignorant of anyknowledge concerning it. But thejury found him guilty and he wasexecuted on April 3, 1936.

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Two photographs, when superimposed, show that the ladder upright and attic floorboard were formerlyone and the same piece, Despite the fact that 1 3/8 inches of wood are missing between the twopieces, nature’s handiwork in the growth rings shows agreement as to curvature, number, variationin width and percentage of summerwood.

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