Dr. Jeffrey MacDonald
The Physical Evidence, Part 1
Wig fibers in Colette's hand
For example, MacDonald's wife Colette held in her hands several strands of long blond synthetic fiber. The fiber was not the same short blond fiber that was used in the doll's hair of MacDonald's daughters, but was the type used in blond wigs. Helena Stoeckley admitted that she wore a blond wig, but had disposed of it shortly after the murders. Also, on Colette's hairbrush some of the blond synthetic fibers were found. Stoeckley admitted after the trial that she had used that hairbrush on her wig that night.
This foreign fiber in Colette's hand could have been the centerpiece of MacDonald's defense if Segal had been properly informed of it. "He had been led to believe that MacDonald's hair...had been tested against another hair in Colette's hand, a longer blond one determined to be her own." (Potter & Bost). As Segal pointed out years later when he discovered the truth, "If it wasn't Jeff's hair, then whose hair was found in Colette's dead hand?"
Hair and skin under the victims' fingernails
Short, brown hair had been found under the fingernails of Colette and the girls, which was naturally and correctly presumed to be the hair of their killer. Analysis showed it was not MacDonald's blond hair, nor the hair of any of the house's inhabitants. A piece of skin was also found under Colette's fingernails which was also presumed to be from her killer. MacDonald had no fingernail scratches when he was taken to the hospital after the murders. The piece of skin was subsequently lost by the Army investigators in their mishandling of the evidence, so no testing of it could be done to prove MacDonald's innocence.
Not only was the knowledge suppressed at the trial that the hair under the victims' fingernails did not match MacDonald's, but a lab technician had written the following note: "[these hairs] are not going to be reported by me." The pressure was on the Army lab techs to keep quiet about anything that made MacDonald look innocent. This was precisely why Segal had wanted those lab notes.