Freeman Hunter III is charged with one count of murder. Investigators say earlier this month he stabbed to death 79-year-old Freeman Hunter Jr.
He has pleaded not guilty.
"Was there some kind of mental defect here? Is there a possible plea of not guilty and not guilty by reason of insanity?" Action News Legal Analyst Tony Capozzi said.
Capozzi explained possible defenses, saying he would look into any previous interactions Freeman III had with doctors and run-ins with the law.
"What's unusual is a son stabbing his father, and (there's) a major age difference in this case, too, which, in itself, is unusual," Capozzi said.
The victim, Hunter Jr., was a retired Fresno police sergeant who served for more than 30 years.
Police Chief Mindy Casto called him a "mentor," and officials at the Fresno County Sheriff's Office, whose deputies responded to the home, are also mourning.
"This guy gave his life to one of the most dangerous professions. He was able to survive, go into retirement, only to find that one of his own family members was the biggest threat that took him out," spokesperson Tony Botti said last week.
The Sheriff's Office is investigating a possible personal dispute or argument before the stabbing, saying it could be "plausible" based on the injuries.
In court Wednesday, the attorneys said little and were later seen huddling with family members after the arraignment. They are preparing for a preliminary hearing that could reveal evidence for the first time.
"Was this done in the heat of passion?" Capozzi said. "If so, it's not a first-degree murder case." Freeman Hunter III is scheduled to return to court on Aug. 19. He remains in the Fresno County Jail, where he will turn 22 on Thursday.
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