A second doctor has found a 22-year-old Santa Rosa man was insane when he killed his father in their Rincon Valley home, setting up a possible lifetime commitment to a mental hospital.

Houston Herczog is accused of stabbing Mark Herczog, 63, more than 50 times in the November 2011 attack.

He pleaded not guilty by reason of insanity and was examined by two psychiatrists who agreed he suffered from paranoid schizophrenia at the time of the slaying, said Herczog's attorney, Karen Silver.

The second court-appointed doctor, Robin Broadman, issued a report Friday stating Herczog believed his father was possessed by an evil force that was trying to kill him, Silver said.

"He thought his life was in danger," Silver said. "He believed who he was killing was not his father."

At a hearing Thursday, prosecutors will challenge the finding and may want to seek a third opinion from their own expert, Silver said.

Prosecutor Bob Waner did not return a telephone call seeking comment Monday.

Silver said the evidence is overwhelming that Herczog, who has a history of mental illness, was suffering delusions when he attacked his father in the kitchen with four different knives. She said it's clear he was unable to distinguish right from wrong.

Silver will ask Judge Dana Simonds to send him to a mental hospital for an indefinite period. He could remain in the locked facility for life or be released in as soon as five years, she said.

"The burden of proof will always be on him to show that he is not a danger to the community," Silver said.

Few people deemed insane at the time of a killing are ever freed. But it has happened recently in Sonoma County. Mathew Beck, who stabbed two Rohnert Park women to death in 2000, was released to a Santa Rosa halfway house last year after about a dozen years in state hospitals.

Beck, who also claimed his victims were evil spirits, pleaded not guilty by reason of insanity in the killings of Sandra Napier, 36, and her mother, Marcella Napier, 63.

Beck was denied release twice before he received the backing of mental health officials, who said he would not pose a risk.

Herczog's family members said he had been suffering from psychiatric problems for more than a year before he attacked his father after returning home from an all-hours gym at 1 a.m.

He has been in a special mental health unit of the jail since his arrest, his lawyer said.

You can reach Staff Writer Paul Payne at 568-5312 or paul.payne@pressdemocrat.com.