A year and a half after police claim Tadarius Lavonte Davis, of Killeen, shot and killed fellow Killeen resident Thomas Gene Smethers in the parking lot of the Copperas Cove Walmart, detectives are searching for a witness who uncovered an "important" yet undisclosed piece of evidence in the case.

Smethers was shot on Oct. 28, 2015. The next day, investigators said someone found the "important piece of evidence" and turned it over to a Walmart customer service representative. The person who located the evidence was never identified and all attempts to find him have been unsuccessful in the more than 17 months since the homicide.

All police know about the individual is that the Walmart employee described him as a white man in his mid to late 50s, possibly driving a tan four-door Chevrolet pickup truck. The man was not involved in the crime, but police want to track him down for the purpose of their investigation.

If anyone has any idea who the man might be based on that vague description, please call Copperas Cove Police Detective Rick Counter at 254-547-8222 ext. 6894.

Davis is charged with capital murder.