Authorities say Peter Robbins was already in jail when he wrote letters to unnamed recipients offering them $50,000 to kill San Diego County Sheriff Bill Gore. Robbins also threatened the manager of a mobile home park.
He faces four years and eight months in prison when sentenced on December 7.
At the time of his arrest, Robbins was at his residence in Oceanside with his dog, Snoopy.
Robbins on Tuesday told the judge that he has been diagnosed with bipolar disorder and paranoid schizophrenia, the LA Times reported.
"I'm mentally ill," Robbins said. "I've committed no crime."
"I want justice to be served, but I’m mentally ill. To stick me in state prison is not benefitting the justice system. I feel I’m entitled to at least a second chance."
Robbins may have already exhausted that second chance. In 2013, he was given probation after pleading guilty to threatening a former girlfriend and the surgeon who did her breast augmentation.
He ended up served four months in jail for probation violations, including drinking, failing to complete an domestic violence class and cutting off his GPS tracking anklet.
From age 9 to 13, Robbins was the voice of Charlie Brown in a series of ‘60s animated classics, including "A Charlie Brown Christmas" and "It's the Great Pumpkin, Charlie Brown."
More recently, he has managed real estate, hosted a radio talk show, and made an appearance at the 2008 Comic-Con convention in San Diego, the Times reported.
