Stephenville, Texas (CNN)A former deputy testified last week that he overheard the defendant in the "American Sniper" murder trial explain why he killed two men. 

Gene Cole, who worked for the Erath County Sheriff's Office at the time, testified Friday that on June 22, 2013, he "heard Mr. [Eddie Ray] Routh say, 'I shot them because they wouldn't talk to me. I was just riding in the back seat of the truck and nobody would talk to me. They were just taking me to the range so I shot them. I feel bad about it, but they wouldn't talk to me. I'm sure they've forgiven me.'" 

Testimony resumes Monday in Routh's trial. He is charged with murder in the February 2, 2013, shooting deaths of Chris Kyle, the former Navy SEAL who was the subject of "American Sniper," and Kyle's friend, Chad Littlefield, at a firing range. 

Routh's lawyer admits his client killed the men but contends he was insane at the time. 

In other testimony, Texas Ranger David Armstrong said investigators searched Routh's residence and found drug paraphernalia, including a pipe commonly used for methamphetamine as well as "a ceramic pipe, what's believed to be a bong, a grinder used to grind different substances and a loose leafy green substance" which lab tests confirmed was marijuana. 

Armstrong also noticed a nearly empty bottle of whiskey in Routh's kitchen. 

Routh's uncle, James Watson, testified that on the day of the slayings he was rousted out of bed by a call from Routh's girlfriend, asking him to come over because she and Routh had been arguing. 
Where does he work?
 Erath County Sheriff's Office