The Atlanta Child Murders
About the finer probability ration involving the car, Dettlinger points out that, "the prosecution used metro Atlanta figures to show how rare this vehicle would be. This means the Williams's vehicle was not included because it was registered in Muscogee County, which is far from Atlanta."
In addition, since four people had been in the Williams home regularly, that made four suspects, not one. "The prosecution summed up by saying that even though the fibers were common, it is the combination of fibers which could not be found in any other environment except the Wayne Williams environment. This gives us four or more suspects, not one, and more importantly: What about a Laundromat where the environments of hundreds, perhaps thousands of fibers are mixed and even clogged together in filters? Clifford Jones was killed in the back room of a Laundromat.
"Clifford Jones was the final blow to the state's fiber case. He was one of only seven who had the even remotely-unique Wellman fiber. However, both the FBI and the investigating officer agree with me that Jones was killed by someone other than Williams and the Jones case was not introduced at the trial even though the defense begged for its submission."
Clearly the fiber probability ratio was not as impressive as it seemed.
This case was the first to have relied on this type of analysis for pivotal evidence, and several appeals justices noted that it was too weak: There were no eyewitnesses, weapon, motive, confession, or clear placement of Williams with any of the victims prior to their deaths. Exactly what did this evidence corroborate? It was not even that clear that the two victims had been murdered, and both were adult males—-completely unlike any of the young boys used in the ten "pattern" cases. It seems obvious from the many problems in this case that fiber alone should not be a deciding factor.
The same can be said for shafts of hair that have only basic distinguishing characteristics. Nevertheless, trace evidence does have its place, as seen in the following investigation.