A 28-year-old US actor was found dead after allegedly killing an 81-year-old woman in a Hollywood murder mystery, police said.

Johnny Lewis, an ex-boyfriend of singer Katy Perry and known for his role in TV series Sons of Anarchy, either jumped or fell to his death after attacking the woman at her house in the Los Feliz neighbourhood east of Hollywood.

Neighbours heard a screaming woman on Wednesday morning and alerted police, who found a woman dead inside the house, from blunt trauma.

She was later identified as Catherine Davis, who rented rooms to boarders.

Two other men received minor injuries after being attacked by Lewis in neighbouring properties, police said.

The actor’s body was found outside on the driveway.

He may have rented a room in the house, according to LA Police Department (LAPD) spokesman Andy Smith.

“It appears that some type of altercation occurred inside the house resulting in the death of the woman,” he said, adding that Lewis either fell or jumped from a roof or wall.

But there was “no one around to push” him, he added, suggesting he may have jumped to his death.

Lewis was known for a role in Sons of Anarchy, about a man struggling to find a balance between being a new father and his involvement in a motorcycle club.

The actor has also appeared in the teen TV series Drake and Josh and the police series CSI: Crime Scene Investigation in 2006.

His big-screen credits include The Runaways (2010), Magic Valley last year and 186 Dollars to Get Out, completed this year but not yet released, according to the IMDb movie database website.