The body of Johnny Lewis, 28, was found in the driveway of the Los Feliz home Wednesday morning after neighbors reported hearing a woman screaming in the home, Cmdr. Andrew Smith said.
The body of 81-year-old Catherine Davis was found inside the home.
"She was possibly beaten," although coroner's officials will determine the exact cause of death, Smith said.
Lewis had rented a room from Davis "for a short period of time" and although there were no witnesses, he is suspected of killing her, Smith said.
No one else was home at the time and investigators were not seeking anyone else for the crime, the commander said.
Reports of a woman screaming sent officers to the home at 10:42 a.m. Wednesday, where they discovered the bodies, Smith said.
Neighbors also told officers that a man had jumped a fence, assaulted a painter and homeowner next door and jumped back.
Smith said that at some point, Lewis jumped or fell from the home's roof, garage or patio.
"He could have fallen from any number of places or he could have tripped or fallen, or he could have jumped. We don't know at this time," he said.
It's also unclear whether drugs or alcohol are involved, Smith said.
Jonathan Kendrick Lewis had a career spanning more than a decade, mainly in small roles. He played Ricky in the 2007 movie "AVPR: Aliens vs Predator Requiem" and was Dennis 'Chili' Childress for two seasons on TV's "The O.C." He played Kip "Half Sack" Epps on FX's "Sons of Anarchy" in 2008 and 2009 episodes.
Calls and messages to Lewis' agent and attorney were not immediately returned.