(CNN) -- A DNA link may signal a break in a 36-year-old investigation into the slaying of four children, the Oakland County, Michigan, prosecutor's office announced Tuesday.
The so-called Oakland County Child Killer is believed to be responsible for the deaths of Mark Stebbins, 12, Jill Robinson, 12, Kristine Mihelich, 10, and Timothy King, 11, who were kidnapped and found dead between 1976 and 1977.
Using technology unavailable to investigators at the time of the crimes, the FBI DNA unit at Quantico tested and analyzed human hairs found on the bodies of Stebbins and King, the prosecutor's office said.
Investigators were able to establish a mitochondrial DNA, or mtDNA, profile link between the hairs, establishing they came from the same person, essentially proving the two crimes were connected.
"This is the first piece of evidence that actually links any of the victims together. It was always believed that these two killings were linked to the same person, however that was an assumption based on the similarities in the crime," said Jessica R. Cooper, Oakland County Prosecutor.
Armed with proof the boys' death was connected, authorities pulled up more evidence from the 1970s investigation. At the time, police had found a person of interest and were able to search his car. The car was a 1966 Pontiac Bonneville. The investigators took samples from the interior of the car and found small hairs, fibers and fur. They were placed in evidence where they remained for decades, until this material, too, was submitted to the FBI DNA unit for testing and analysis.
According to prosecutors, the testing revealed that the hairs recovered from the Bonneville had the same mtDNA profile as the hairs recovered from the boys' bodies.
The owner of the car, 70-year-old Archibald "Ed" Sloan, is serving a life sentence for two counts of criminal sexual conduct in the first degree. Sloan was tested for a DNA match, but it was determined he did not share the same DNA profile: The hairs found on the boys and in the car were not his.
"It is believed that Sloan would allow others to use his 1966 Bonneville, as well as the other described vehicles, so investigators are looking for information concerning any other people who may have used this car, or had access to any of these vehicles. Finding anyone like this who turns out to be the donor of the hair may be the key to solving these two murders," Cooper said.
The mtDNA results are not absolute.
According to prosecutors, the hairs recovered from the boys' bodies were not suitable for autosomal DNA testing, or nuclear DNA testing, the testing most commonly referred to in movies and television. Investigators had to use mtDNA testing, which is less definitive than autosomal DNA testing.
"With nuclear, autosomal DNA ... you're dealing with absolute identification. It's like a fingerprint, unique to each person except twins," said Dr. Lawrence Kobilinsky, forensic scientist at John Jay College of Criminal Justice, "Mitochondrial DNA is completely different. If you have a hair from a person, that person's siblings and all maternal relatives would share that mitochondrial profile. It's not unique to a particular person."
On the other hand, Kobilinsky said an mtDNA link is still significant, and enough to cast suspicion on anyone who shares the mtDNA profile, "People have been convicted on mtDNA evidence alone," he said.
Authorities are hopeful the new evidence will help them catch the killer.
"We are excited about this new opportunity," said Oakland County Sheriff Michael Bouchard, "This haunts every police officer who was around then and is around today."
Authorities encourage anyone with information to call the tip line at 1-800-442-7766.