Crime Library: Criminal Minds and Methods

Dr. Jeffrey MacDonald

The FBI Laboratories

The government's chief forensic expert was Paul Stombaugh, who had at one time been in charge of the chemistry laboratory at the FBI.  The pleasant and confident, elderly Stombaugh made an excellent witness, bringing with him the credibility and prestige of his former position at the FBI.  Even though Bernie Segal was able to demonstrate that Stombaugh had received only one year of formal training in chemistry and that his grades in chemistry were poor, the judge did not allow him to present that information to the jury.  Consequently, the credibility of the witness remained unchallenged.

Stombaugh had a new theory  that certain bloodstains on MacDonald's pajama tops indicated that the tears on fabric occurred after the blood stained the pajama top.   If proven, it suggested that MacDonald got Colette's blood on him as he allegedly fought with her.  This new theory was proposed without giving the defense a chance to examine the documents on which the theory was based.  Visual examination of the pajama tops did not support this theory.

When Segal asked for the photographic evidence to support this dangerous new theory, Stombaugh was not able to prove it in court, but maintained that it was so.  Thus, the jury heard very damaging new testimony, even though there was no way to refute it or disprove it during the trial.  Years later, when the defense team finally got it hands on the lab notes through the Freedom of Information Act, they found that  the Army's "CID lab tech Janice Glisson years earlier had explored the same bloodstain theory and had come to a different conclusion.  She had determined that the stain edges on either side of the rips did not intersect, that the pajama tops was therefore, stained [after] it was ripped, not before." (Potter and Bost)


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