Cops discovered the body of the Sons of Anarchy star, who once dated singer Katy Perry, in a driveway in the Los Feliz neighbourhood on Wednesday (26Sep12).
An 81-year-old woman, believed to be the owner of the house, was discovered dead inside the property. Police sources tell TMZ.com she was the victim of a homicide.
Neighbours have reported hearing the elderly woman screaming, before spotting Lewis climbing onto the roof of the home, according to local TV reports.
It remains unclear what caused Lewis to plunge to his death.
Lewis, aged 28, also had roles in TV shows including The O.C., Bones and Criminal Minds, as well as Hollywood movie The Runaways with Kristen Stewart.