Nearly 17 years after the decomposing bodies of two men were found along I-75 in Independence Township, investigators have not given up on determining who killed them.

The Oakland County Sheriff’s Cold Case Unit is still seeking any clues the public can provide to help solve the slayings of Terry Lee Holbin, 51, and Ronnie Ralph Tripp, 55, who were retired, had lived together in Flint and were estranged from their families, the sheriff’s office said.

A surveying crew working in the area discovered the bodies in April 2008 under some trees along the freeway’s northbound side, just south of the M-15 exit. Holbin and Tripp had been shot in the head by a small caliber firearm, the sheriff’s office said.

The bodies had extensively deteriorated, and DNA analysis was required to positively identify Holbin and Tripp, the sheriff’s office said. The deaths were ruled as homicides.

The last known sighting of the two men was in October 2006, and it’s believed they were shot several months before the bodies were discovered, the sheriff’s office said.

Investigators haven’t much more on the case besides the victims’ names, and viable tips were looked into long ago, the sheriff’s office said. According to Det. Sgt. Matt Peschke of the sheriff’s Special Investigations Unit, no one has been ruled out as a suspect.

A year after the bodies were found, detectives learned that Holbin owned a 1999 Chevrolet pickup truck which was eventually located after it was set on fire; the vehicle turned out to be of little evidentiary value, the sheriff’s office said.

Despite the years that have passed since the homicides, Peschke still holds out hope.

“There have been extensive investigations over the years, the circumstances surrounding their deaths remain unresolved,” Peschke said. “The sheriff’s office is urging anyone who may have information, no matter how small, to come forward. This case has remained open, and any new leads could be crucial in bringing closure to this mystery.

“If you witnessed any suspicious activity in the area during that time or have any knowledge that could assist the investigation, please contact the Cold Case Unit immediately,” he said. “You may remain anonymous. Your information could make a significant difference in solving this case and providing answers for the families of the victims.”

Added Sheriff Mike Bouchard: “We never give up on finding the perpetrators in heinous cases like this to not only hold them accountable for their actions, but to give the family some sense of closure. The public’s help would be greatly appreciated and if they have any information that could lead to the arrest and conviction of someone, they would be eligible for a reward.”

Anyone with any information about the case is asked to call Crime Stoppers at 1-800-SPEAK-UP. Crime Stoppers is offering a reward of up to $2,000 for information leading to an arrest.Tipsters remain anonymous.