The defense team for Jerry Lynn Burns rested its case Thursday, posing questions about whether key DNA evidence is simply circumstantial. The 66-year-old Manchester, Iowa man faces a first degree murder charge in the 1979 killing of Cedar Rapids high schooler Michelle Martinko, who was found stabbed to death in her familys Buick in the parking lot of the Westdale Mall.

Prosecutors have made DNA evidence central to their case against Burns. The defense team has worked to raise questions about whether crime scene materials have been properly handled over the past 40 years, and have questioned whether Burns genetic material could have been transferred to the crime scene by chance.

Analysts from the Iowa Department of Criminal Investigation and private firms engaged by the prosecution have testified that Burns DNA is consistent with a male genetic profile developed from a bloodstain on the dress Martinko was wearing when she died. Jurors have also heard testimony that a partial genetic profile developed from blood found on the car gear shifter is also consistent with Burns DNA.

DCI analyst Linda Sawer identified the profile during tested she conducted in 2005. It wasnt until years later that Cedar Rapids Police Department investigators, led by Officer Matt Denlinger, were able to upload the profile to family genealogy website GEDmatch. On the site they found a second or third cousin once removed of the subject and were able to establish a family tree, which ultimately led them to Burns in 2018.

On Thursday, the defense team called their first and so far only witness, private forensic genetics consultant Michael Spence. He was hired to review the case files, and genetic sampling and analysis conducted by DCI and private firms DNA Labs International and Bode Technology.

"At crime scenes there can be [DNA] transfer events from people who arrive at that crime scene, prior to the crime scene, during the crime scene, after the crime scene, there can be transfer events." - Michael Spence, forensic genetics consultant

Through his questioning of Spence, defense attorney Leon Spies worked to establish that DNA can be transferred from person to person simply in passing. Spence testified that there is a robust body of evidence on the secondary transfer of DNA, when one individuals genetic material is transferred to someone or something else, simply by touching items, or physically being in a place and naturally leaving behind millions of skin cells, each containing DNA.

Shaking hands is an easy example. Hugging, Spence said. If you touch the other people, if they talk around you, if they leave DNA on an item and you come over and sit down next to it or on it, those kinds of things. This is how transfer events do occur.

Spence did not dispute that Burns DNA is consistent with the male genetic profile developed from a bloodstain on Martinkos dress. But based on the genetic analyses that have been conducted, he said its not possible to know the exact sequence of events that night, or to say exactly when Burns DNA came into contact with the dress.

At crime scenes there can be transfer events from people who arrive at that crime scene, prior to the crime scene, during the crime scene, after the crime scene, there can be transfer events, he testified.

Under questioning by Spies, Spence testified that it is within the realm of possibility that Burns DNA ended up on the dress due to a secondary transfer, and not necessarily during the commission of the crime.

Is it, Dr. Spence, a plausible explanation that the DNA of Jerry Burns found on the dress or on the gear shift couldve come about by a transfer? Spies asked him.

Yes, thats a distinct possibility, Spence replied.

"It's extraordinarily difficult to reconstruct what happened 40 years ago, isn't it?" - Leon Spies, defense attorney for Jerry Lynn Burns

During cross examination, prosecutor Nick Maybanks challenged Spence repeatedly, questioning him about the body of peer-reviewed scientific evidence backing up his stances. Maybanks cited multiple journal articles by different authors in his questioning, pressing Spence on the myriad of factors that can affect whether and how much DNA could be transferred during a given interaction.

Through his questioning of Spence, Maybanks worked to establish that people are much more likely to leave behind more DNA by a wet transfer (of blood or other body fluids) than by a dry transfer (such as skin cells deposited during a handshake), as well as when theres a greater level of friction involved, as would occur in a physical attack.

Theres a pretty distinct difference here, that the transfer between wet and dry substances is 44 to 100 percent versus less than a 1 percent respectively, right? Maybanks asked.

It is a higher rate of transfer with body fluids and liquids, yes, Spence replied.

Maybanks questioned Spence on whether hes encountered any evidence supporting how Burns DNA couldve been transferred to the dress (other than by him physically Martinko).

Prosecutors have not been able to establish any previous relationship between Martinko and Burns, characterizing the crime as a random act of violence committed by a stranger."

In this case would you agree that based upon your analysis of the case that you didnt find any evidence whatsoever putting Jerry Burns in a position to transfer DNA other than speculating or creating events that that took place? Maybanks asked Spence.

Well, I refuse to speculate up here, Spence responded. And it would be incredibly difficult to do so, especially with a 40-year-old crime.

The defense team continued to press just this point: how can the prosecution definitively prove exactly what happened on that night in 1979?

Its extraordinarily difficult to reconstruct what happened 40 years ago, isnt it? Spies asked Spence.

Absolutely, Spence replied.

On Thursday, Burns formally waived his right to testify on his own behalf. The trial is slated to continue Friday, when prosecutors will have the chance to call rebuttal witnesses.

Read more here:
Man Accused Of Killing Martinko Won't Testify As Defense Rests Its Case - Iowa Public Radio

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