The crime was a contract murder. 18 latent prints lifted by 3 different crime scene officers had been identified to the hit man. The case was in a different city. I was not involved.
But then the suspect alleged that years earlier, he had been kidnapped by drug dealers who had cast his hands at a prosthetics laboratory and made gloves with his fingerprints. The drug dealers were using those gloves to frame him. The prosecutor recognized that a jury might believe even the most ridiculous story if it went unchallenged. He had read my published research on forged and fabricated latent print evidence. He phoned and asked if I could distinguish between prosthetic glove prints and real friction ridge skin (FRS) prints.
I told him that I would have to study and experiment. I needed to become an expert in prosthetic glove prints before I could answer his question. The trial was still six months off. We had time.
I contacted the leading companies that make prosthetic gloves in the US and Europe to learn about the manufacture process. I obtained gloves for testing. I deposited and lifted hundreds of prosthetic glove prints and spent hours examining and comparing them to FRS prints under a 25X stereo microscope. I developed a 23-point examination protocol to use for analyzing the evidence latents. In combination, those 23 points of analysis could be indicative of gloves or FRS prints.
I made what I considered a logical step to the fundamental assumption that either all 18 prints were glove prints, or they were all FRS prints. There could not be some glove prints and some FRS prints.
I finally began my analysis of the latent prints. Using the 23-point analysis protocol, I spent an hour or more examining each crime scene latent under the stereo microscope. I took over a page of handwritten notes on narrow lined paper describing each latent. Consideration of the total of 23 points for 18 latents led to a firm conclusion that the latent prints represented the touch of FRS on the surfaces where the prints were developed. They were not made by prosthetic gloves. I had the data. I had close-up photographs to demonstrate the microscopic differences. I issued a detailed report on my findings.
The trial was expected to last two weeks. I was scheduled to testify as a rebuttal witness during the second week. But the prosecutor called me in a panic just days before I was to appear and told me I could not testify to any of my experiments or conclusions. A latent print examiner for the investigating agency had just testified to the identifications. But during cross examination, the defense attorney asked her if she could tell the difference between prosthetic glove prints and real fingerprints. She shocked the prosecutor and the court by revealing that she had obtained a glove, made prints with it, and by naked eye or maybe with a regular comparison loupe, she had concluded that prosthetic glove prints were perfect. She testified that it was impossible to distinguish between glove prints and real prints.
Her five-minute experiment not only came to the wrong conclusion, but she had also not disclosed to the prosecutor what she had done. She testified to it nonetheless, gave the jury bad information, and unwittingly blocked more competent research from being presented.
The moral of the story is this: Never overextend yourself or testify to anything for which you are not qualified. If you’re going to express an opinion, do your due diligence to support it.