Report of the President's Commission on the Assassination of President John F. Kennedy

General Principles

This section introduces the general principles of microscopic forensic examination applied to hairs and fibers. It establishes that while individual hairs are not unique in the way fingerprints are, an expert can typically distinguish hairs between different individuals and between human races (Caucasian, Negroid, Mongoloid) based on multiple characteristics. Stombaugh is cited as having performed approximately 1,000 Caucasian hair comparisons and 500 Negroid hair comparisons without finding any indistinguishable Caucasian pair.

Hairs

Hairs consist of a central medulla of air cells, a cortex containing pigment granules and cortical fusi, and a cuticle with an outer scale layer. Although not individually unique like fingerprints, human hairs can be distinguished from animal hairs, and hairs from different racial groups can be differentiated by color, texture, size, diameter fluctuation, cuticle thickness, pigment distribution, and cross-sectional shape. Experts can usually distinguish hairs of different individuals.

Fibers

Both natural and artificial fibers can be distinguished microscopically, though individual fibers are not unique. Color is the major identifying characteristic, with microscopes revealing 50–100 shades of green or blue and 25–30 shades of black. Three fiber types are discussed: cotton (a natural fiber resembling a twisted soda straw, available mercerized or unmercerized), wool, and viscose (an artificial fiber typically containing a delustering agent appearing as tiny spots, with hundreds of possible diameter variations).

The blanket

Commission Exhibit No. 140, received by Stombaugh on November 23, 1963, was composed of approximately 1–2% woolen, 20–35% cotton, and the remainder delustered viscose fibers. The viscose showed 10–15 different diameters and shade variations (suggesting scrap viscose), while the cotton showed seven to eight shades of green but uniform twist. The blanket was folded into a narrow right triangle shape with a safety pin and string tied in a granny knot with bow-knot dangling ends. A 10-inch hump in the blanket matched the length and shape of the C2766 rifle’s telescopic sight. Foreign hairs and fibers were found, with several limb and pubic hairs matching Oswald’s samples in numerous distinctive characteristics; other hairs did not match Oswald.

The paper bag

Commission Exhibit No. 142, received November 23, 1963, showed only fingerprint powder and insignificant white cotton fibers on its exterior. Inside, examiners found a minute wood fragment, a waxy particle, a single brown delustered viscose fiber, and several light-green cotton fibers. The brown viscose fiber matched blanket viscose fibers in shade, diameter, and delustering agent distribution, and each green cotton fiber matched blanket green cotton fibers in shade, twist, and unmercerized condition.

The shirt

Commission Exhibit No. 150, received November 23, 1963, was composed of gray-black, dark blue, and orange-yellow cotton fibers. The orange-yellow and gray-black fibers were uniform in shade, while the dark-blue fibers came in three different shades. All fibers were mercerized with substantially uniform twist.

The C2766 rifle

Commission Exhibit No. 139, received the morning of November 23, 1963, had been dusted for fingerprints, causing Stombaugh to doubt finding exterior fibers. Most fibers found were dirty, old, fragmented, and lodged in crevices or on greasy deposits. However, a “fresh” tuft of clean, unfragmented fibers had caught on a jagged edge where the metal butt plate met the wooden stock and was folded into the crevice by the fingerprint brush. The tuft contained six or seven orange-yellow, gray-black, and dark-blue cotton fibers that matched comparable shirt fibers in shade and twist. Stombaugh concluded the fibers could easily have come from the shirt, though identical shirts could not be excluded.

Photographs

Two photographs of Lee Harvey Oswald holding a rifle were found in Mrs. Ruth Paine’s garage at 2515 West Fifth Street in Irving, Texas: Commission Exhibit No. 133-A (rifle held in front of body) and 133-B (rifle held to his right). A negative of 133-B and photographs of General Walker’s house rear were also found there. An Imperial reflex camera, which Marina Oswald testified she used to take the photographs, was later produced by Robert Oswald. FBI photographic expert Lyndal D. Shaneyfelt testified regarding the photographs, negative, and camera.