A woman brutally and fatally stabbed in her car after visiting a shopping centre may have helped solve her own murder almost 40 years after her death.
Michelle Martinko, 18, was killed just before Christmas on December 19, 1979, outside a Westdale Mall in Cedar Rapids, in the US state of Iowa.
The high school student was reported missing and after searching for hours, police found her bloodied body in her parents’ Buick the next day.
Her lungs and aorta were pieced, and she lost about a third of her blood.
Evidence was collected from the crime scene, including Michelle’s dress and blood scrapings from a gearstick.
The prime suspect in the murder was a man named Andy Seidel, the ex-boyfriend of Michelle who ran into her at the mall the night she was killed.
For years Seidel walked around town with people believing he was the killer, but once DNA could be used as a forensic tool, he was cleared of any wrongdoing when his DNA didn’t match the evidence.
This raised many more questions for police, with the only lead being that the killer was a man.
How genealogy database helped find killer
With police left with no leads and the killer still a mystery in 2015, a photo of a suspect was created after DNA technology advances could provide a profile including hair colour, eye colour and race.
After releasing the photos and receiving hundreds of tips, detectives didn’t know where to turn to next.
That was until the Golden State Killer was arrested and charged over a long spree of murder and rape after police matched his DNA with a relative who submitted their own for genealogy testing.
Detective Matt Denlinger, investigating the case of Michelle, told CBS’ 48 Hours they tested the DNA found on her dress and in the car alongside any submitted to public national database GEDmatch.
In a massive breakthrough, they found a match, with detectives led to the second cousin of the killer.
After building the woman’s family tree, they were led to three brothers who shared some DNA with the blood they had on file.
After collecting DNA samples from the brothers in 2018, police zeroed in on one of them in particular – Jerry Burns.
While he didn’t match the stereotypes of a killer – with a wife, three kids and a job as a respected businessman – his DNA investigators secretly collected from a straw told a different story.
While Burns said there was no plausible reason why his DNA would be in the car, he was arrested on December 19, 2018, 39 years to the day after Michelle was found dead in her parents’ car.
He was convicted of first-degree murder this February and sentenced to life in prison with no chance of parole.
How Michelle solved her own murder
Detectives told 48 Hours Michelle’s killer may have never been brought to justice without the blood DNA evidence both on the gearstick in the Buick and on the 18-year-old’s dress.
Despite it being almost 40 years until an arrest was made, it would likely still be a cold case if Michelle didn’t play such a unique role in solving the investigation.
“She fought so hard that she caused the murderer to cut himself, he left his DNA ... and so Michelle helped solve her own murder,” her sister Janelle Stonebraker told 48 Hours.
With Burns now serving life in prison, the 67-year-old still maintains his innocence.