Only one remains unsolved.
On Jan. 20, 1985, 55-year-old Bill Gillispie was found fatally shot behind an abandoned house on his property in northwest Archer City.
Staci Beesinger, Archer County sheriff, says, "A call had come into the sheriff's office that he may have been missing. The deputy went by there at about 3 a.m. and he was found at the back of the building laying on the ground."
Though many were questioned, no one was ever arrested for the crime.
"There have been several promising leads, different suspects," says Sgt. Simon Dwyer, the lead investigator in the case.
"Technology hasn't been able to get us to a point where we can be certain of the suspect or suspects."
Dwyer decided to re-open the case on Jan. 20 of this year, the 27th anniversary of Gillispie's murder.
"There is some new technology involving DNA, particularly touch DNA and familial DNA that may make a break in this case, or may have already made a break in this case," Dwyer says.
He says he's working with multiple agencies, including the FBI and several out-of-state agencies, to get this cold case solved.
Right now, investigators with the Department of Treasury and another federal agency are processing evidence and working some leads.
Dwyer says after that information comes back, he thinks it's only a matter of time until a major break is made in this case.
"We owe it to the family and to Bill to bring him some justice. Any murder needs to be solved and justice served," Beesinger says.
"I'm hopeful that once all the facts are collected, we can connect the dots, so to speak, and make a very solid case against the person or persons that did this," Dwyer says.
If you have any information about this crime, contact the Archer County Sheriff's Office at (940) 574-2571.
Next week, Melissa takes a look at the 1996 murder of Zemether Scroggins IV, who was found fatally shot inside his car.
Copyright 2016 Nexstar Broadcasting, Inc. All rights reserved. This material may not be published, broadcast, rewritten, or redistributed.