A Texas man accused of shooting and killing his wife in 2013 says it happened while he was sleepwalking.

Raymond Lazirene, 67, appeared in a Houston court Monday for the start of his trial where he stands accused of shooting and killing his wife, Deborah, in 2013. While Lazirene has not denied pulling the trigger, his lawyer has argued it happened while Lazirene was sleepwalking and suffers from a medical condition.

“Our position over here is this was a dream and it wasn't voluntary,” Lazirene’s lawyer, Feroz F. Merchant, told Houston NBC-affiliate KPRC. “And he does, we've had him evaluated, and obviously the experts are going to come by and say hey, we think he suffers from a medical condition where it's involuntary.”

The shooting happened on the afternoon of Dec. 18, 2013. Lazirene reportedly called his son, Nathan, while he was at work and asked him to come home after having a dream of killing his wife. When the younger Lazirene arrived, he allegedly found his mother’s dead body in the house’s living room with six gunshot wounds. Police arrived shortly after and arrested the elder Lazirene, who maintained everything felt like a dream.

“He mentioned something there that was more of an off the wall comment about, ‘This is like a dream. I wish I could wake up from.’ Something along those lines,” Retired Houston homicide detective Fil Waters told KPRC.

However, Lazirene’s son testified that there is some validity to his father’s claims. He told the court Monday that his father has been receiving psychiatric care for nearly a decade. He also said his father also has to take prescribed psychotropic drugs, which he sometimes mixes with alcohol.

Lazirene faces life in prison if found guilty.

Courtroom This photo shows a view of the defendant's table in a courtroom closed due to budget cuts and layoffs, at the Stanley Mosk Courthouse in downtown Los Angeles, March 16, 2009. Photo: Robyn Beck/AFP/Getty Images