CEDAR RAPIDS — A straw used to sip soda led authorities to the Manchester man two months later they would charge with fatally stabbing 18-year-old Michelle Martinko in 1979.

DNA from two distant cousins led to three brothers, and DNA from one of the brothers — Jerry Lynn Burns, 64 — matched the blood stain from Martinko’s dress, according to a search warrant affidavit.

The probability of finding Burns’ DNA profile among unrelated individuals would be less than one out of 100 billion, according to the document.

The case that went cold for 39 years wasn’t jump-started until investigators learned in May 2018 they could use genetic genealogy.

Parabon-NanoLabs in Reston, Va., told investigators about GEDMatch, a public DNA database used to help research family trees. The DNA of the suspect was uploaded to the site and showed shared DNA with a known cousin on the site.

Parabon officials told Cedar Rapids police investigator Matthew Denlinger the match was a cousin once removed from the suspect, and the lab had been able to create a family tree with four sets of the cousin’s great-great grandparents at the top, according to the warrant.

Parabon told Denlinger if he could collect DNA samples from living relatives of each set of grandparents, he then could identify which branch of the family tree belonged to the suspect.

Denlinger, in the warrant, said he collected DNA from two branches of the family tree, which were eliminated, but on the third branch a first cousin was identified as sharing DNA with the suspect. Parabon officials told Denlinger that the suspect likely was one of three brothers, which included Burns and his two brothers, the warrant shows.

Denlinger then checked driver’s license records, which revealed all three brothers grew up in Manchester, Iowa. Jerry Burns and one brother lived in Manchester and their other brother had moved to Davenport, according to the warrant.

Denlinger assisted with surveillance on all three brothers and covertly collected DNA from items.

In October 2018, Denlinger watched Jerry Burns at a restaurant drink several sodas using a clear straw. The investigator collected the straw after Burns left the restaurant.

The DNA on the items from two brothers were eliminated as potential matches to the dress blood stain, according to the warrant. But a Nov. 5 Parabon report showed the Jerry Burns’s DNA taken from the straw matched the suspect’s.

The warrant also reveals more of the interview that Denlinger and another investigator conducted for more than an hour with Burns at his business, Advanced Power Equipment and Coating Concepts, in Manchester on Dec. 19.

Burns denied knowing Martinko or being involved in her death. He also denied being at the crime scene, even after being confronted with the DNA evidence.

But he couldn’t provide a plausible reason why his DNA would be found, Denlinger said.

Burns showed “almost no emotion” during the interview or after being told he was going to be arrested, Denlinger noted in the warrant. Burns — who had refused to voluntarily provide a buccal, or cheek, swab — during questioning repeatedly asked investigators to test the swab he provided to them after a search warrant was submitted.

During the interview, Burns made and accepted phone calls and texts after being told what case was being investigated and why police wanted to talk to him, according to the warrant.

After one text, investigators heard Burns discussing police surveillance with someone on one these calls, Denlinger said.

During the interview, Burns admitted he was familiar with Martinko’s slaying and remembered hearing about it at the time it happened. But said he hadn’t followed the case and wasn’t familiar with the recent developments.

He did say he was familiar with genetic genealogy. Denlinger said that seemed to him like an “odd” statement — if Burns hadn’t followed this case or similar ones — given that genetic genealogy is a “distinct sub-specialty” of genealogy and only recently has gained media attention because law enforcement has used it to solve crimes.

After Burns was arrested, a search warrant was issued Jan. 10 for his phone, but an investigation showed no browsing or any internet history, suggesting Burns had used that phone for calls and texting only.

Investigators then issued a search warrant for Burns’s home and office desktop and laptop computers. Investigator Jeff Holst with Cedar Rapids police found Burns’s office computer included search activity involving “blonde females, assault, rape, strangulation, murder, abuse and rape of a deceased individual, and cannibalism.”

Holst pointed out in the search warrant affadvit he believes a person’s browsing history can reveal sexual preferences, desires or fetishes, as well as establish a general timeline of what days and times the person uses the computer and for what purpose.

Holst also noted that Martinko was an 18-year-old blond woman who was attacked, assaulted with a blunt force injury to her head and stabbed about 21 times. She had defensive wounds consistent with fighting off her attacker before she died.

Investigators didn’t discover any evidence that Burns and Martinko had a previous relationship or even knew each other before this incident, the warrant showed.

No evidence has been found that would indicate any connection between the two other than the fatal attack was motivated by Burns’ desire to harm, sexually abuse and/or kill, according to the warrant.

Martinko was found stabbed to death in her family's Buick on Dec. 19, 1979, in the parking lot of Westdale Mall. The Kennedy High School senior had left a school choir banquet that night and drove to the mall to buy a new winter coat.

Her body was found early the next day, according to court records.

A DNA profile was developed from blood found on Martinko’s clothing and on the gear shift of the vehicle, police said.

Burns, who has pleaded not guilty to first-degree murder, remains in jail on a $5 million cash only bail. His trial is set for Oct. 14 in Linn County District Court.

l Comments: (319) 398-8318; trish.mehaffey@thegazette.com