(Cover) - EN Showbiz - Johnny Lewis was a "really good guy", says his Sons of Anarchy co-star.

The actor and an 81-year-old woman identified as Catherine Davis were found dead by the Los Angeles Police Department this week.

It is alleged that Johnny murdered Catherine, his elderly landlady, before he fell to his own death. Authorities believe the 28-year-old star may have been under the influence of Methamphetamine or PCP at the time.

Despite the mystery surrounding the deaths, Johnny's Sons of Anarchy co-star Kenny Johnson claims he's been in disbelief since hearing the news.

"It's sad man... I'm sad, I'm bummed, I've been in shock all day," he told TMZ. "He's a really good guy."

Johnny - who formally dated Katy Perry - has also been remembered by Nikki Reed. The two starred alongside each other on The O.C., and Nikki has expressed her sadness at the "horrible and shocking" news.

"He was the nicest guy," she said. "I never thought anything but great things about him. I have nothing to say except that he was a really nice guy. It's just crazy."

Johnny's behaviour had reportedly become increasingly erratic, and he was on supervised probation after a string of arrests.

Probation officers wrote they were "very concerned for the well-being of not only the community but that of the defendant," earlier this year.

Meanwhile, it's been claimed that Johnny suffered a "psychotic break" after taking an undisclosed drug earlier this year.

Sources told TMZ the episode made him "mentally unstable" and he "began to 'self-medicate' to deal with the problem."

Those close to his family don't believe the deaths were caused by drugs, rather that he "stopped taking his meds and became extremely unstable and violent". (C) Cover Media