The body of the couple's dog, Teddy, was found near the grave.
The Tillman's vehicle was located five days later in Van Nuys. An exhausted investigation seemed to go nowhere.
"They looked into many different parts of their lives. They were looking for some sort of suspect information, but they found nothing," said Cindy Beavers, from the San Bernardino County Sheriff's Department.
After years the case went to the cold case files.
"It has been eight years now and the sheriff's department now has a cold case team. This is one of the cases that they recently have been working on," said Beavers.
A caller remembered something that might help detectives in the case. He remembers seeing two men in the wash a few days before the Tillman's bodies were found.
One of the men is a person of interest. He is described as a white male in his late 20s to early 30s. He had long brown or black hair and was wearing a baseball cap.
There was no description of the second man. They were travelling in a green Ford Bronco.
"That is the only lead that the investigators have. They believe that this person may of seen something. They may have some information. They are not saying necessarily that these men in the Bronco were involved in their murder," said Beavers.
If you have any information regarding this case you are asked to call the We-Tip hotline at (800) 78-CRIME or (800) 782-7463.