Trevor Seifert, Crime Lab Analyst

He is a senior crime laboratory analyst with the FL department of Law Enforcement. He has just over 17 years with them. Until September 2022 he was in the biology section of the Pensacola regional operations center where they do DNA analysis.

Seifert has a bachelors of science in biology from Southern Oregon University and a PhD in microbiology and immunology from the University of Florida. He went through a 1 year training program in forensic biology. Required annual continuing education and keeps up to date with current literature
Seifert has been qualified to testify as an expert in two different court circuits. He has testified approximately 55 times, first time in Colorado.
For today's hearing, he is qualified as an expert in forensic DNA analysis. Judge explains what makes someone an expert - their training or education - but says they are not bound by what an expert says and may question their credibility just as any other witness.
Seifert is asked to explain what DNA is and where it comes from; it's a molecule found in every cell of your body except for mature red blood cells.
STR DNA analysis is short tandem repeats, they do that at the Florida Department of Law Enforcement. The number of markers differ between individuals and create a unique profile. 21 DNA markers and 3 gender markers.
A DNA profile is made from a sample of biological material using chemical processes opening cells and releasing the DNA into a solution and using an instrument that quantifies the amount of DNA obtained. If a high enough amount is obtained, polymerase(?) chain reaction is used to amplify each of the 21 markers which enables another analyzer to measure the lengths of the fragments to determine the number of STR which gives a profile of the individual.
Depending on the number of markers, statistics differ with how unique it will be. Overall, a DNA profile is unique to an individual and only an identical sibling will have the same DNA profile.
Half of your DNA is from your mother, half is from your father. Two copies of the markers which give a number of short tandem repeats (STRs).
Depending on the type of case, where the DNA is compared (which database) changes.
There are different DNA databases that agencies nationwide can enter profiles into.
The majority of DNA comes from blood, semen, saliva, tissue, and also items that people have worn using epithelial cells, or hairs.
DNA is stable in dry and cold environments. In the natural environment, DNA degrades. The human body releases enzymes that break down the cell and breaks up the DNA.
Microorganisms break up DNA. Hot and humid, wet or damp environments, DNA is degrading rapidly.
After March 18th 2020, Seifert was asked to do DNA analysis to confirm the identity of the body found under the bridge.
Using a buccal swab, a card with a few types of blood, he used the previously mentioned methods. The blood sample did not give enough DNA for a profile; the buccal swab did but the results were inconclusive.
Seifert was aware of the source of the DNA and was not surprised he could not develop a profile due to the level of decomposition; harder tissue such as bone or teeth is usually needed for such cases.
Seifert swabbed tissue from a rib bone and took a cutting of the rib bone and did the same processes; the swabbing was not enough for a profile and the cutting was not enough to obtain a usable profile. He went back and then got bone marrow, same process, and could not interpret the results. Repeated this process and was finally able to obtain a usable partial profile. He had 9 of 21 markers.
Using the 9 markers, Seifert compared his profile to the profile of Gannon Stauch from the El Paso County Sheriff's Office; it matched. Seifert considered it confirmation of the identity but if it had been his case going forward he would have tested further.
Seifert does not know whether any further testing was completed as the Colorado Springs authorities took over the investigation.