Police received a call Wednesday morning (local time) about a screaming woman in the affluent Los Feliz neighbourhood and responded to find Catherine Davis dead in her home, said Los Angeles Police Department Officer Cleon Joseph.
Joseph said Lewis, 28, was also dead in the home's driveway after either falling or jumping off the roof.
The officer said the circumstances around the deaths were still being investigated.
"Detectives believe that he may have committed the murder," Joseph said of Lewis, adding that the motive was unknown.
Lewis had a supporting role in the first two seasons of "Sons of Anarchy," a television drama featuring an outlaw motorcycle club. He played Kip "Half Sack" Epps, an Iraq War veteran who hangs out with the biker club featured in the show.
The Los Angeles-born Lewis previously had recurring roles in the TV shows "Boston Public" and "The O.C."
