'Sons of Anarchy' actor found dead

"Sons of Anarchy" actor Johnny Lewis attends the 2011 Tribeca Film Festival.

• Johnny Lewis' acting resumé included "The O.C." and "Criminal Minds"
• Lewis, 28, apparently climbed on the roof and fell to his death, police say
• Katherine Davis, 81, was found dead inside the home in a "gruesome scene"

Los Angeles (CNN) -- The violent deaths of "Sons of Anarchy" actor Johnny Lewis and an elderly woman in an affluent Hollywood neighborhood Wednesday is a murder mystery for Los Angeles police.

Lewis, 28, whose acting resumé included "The O.C." and "Criminal Minds," died in the driveway of a three-story home in the Los Feliz neighborhood near Griffith Park, apparently after climbing on the roof and falling, police said Thursday.

Police, responding to a call from neighbors saying they heard screams for help from a woman inside the house, found Katherine Davis, 81, dead in what a police spokesman called a "gruesome scene."

"It appears that some type of altercation occurred inside the house, resulting in the death of the woman, then this individual ran outside and had an altercation with a couple of neighbors," LAPD Commander Andrew Smith told reporters.

Autopsies will be conducted Thursday on the bodies of Lewis and Davis, Los Angeles County Coroner's Lt. Larry Dietz said.

Police would not comment on the possibility of drugs being involved in the case.

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CNN's Jane Caffrey contributed to this report.