Son arrested in deadly Castro Valley stabbing while trying to defend mother, deputies say
Street signs showing Seven Hills Road and Parsons Avenue in Castro Valley, Calif. on Sept. 8, 2026.
CASTRO VALLEY, Calif. - A 20-year-old man is in jail on suspicion of murder after allegedly stabbing his father to death while trying to defend his mother during a physical fight at their Castro Valley home.
The incident occurred around 1:30 p.m. Saturday at a residence on Parsons Avenue near Seven Hills Road, where the family has lived for about a year.
Son arrested
What we know:
According to the Alameda County Sheriff's Office, a 51-year-old man and his wife were engaged in a physical altercation when their son heard his mother in distress.
Authorities say the son retrieved an "edged weapon" and stabbed his father, who later died at a hospital.
KTVU has learned the suspect is 20-year-old John Thomas Powell, who is being held without bail on suspicion of murder.
Castro Valley neighborhood reaction
What they're saying:
Neighbors described a heavy law enforcement response following the altercation.
Nora Patterson watched the scene unfold from her porch as officers arrived with weapons drawn, followed by a continuous stream of responding police vehicles.
"It's tragic, you know? He lost his life. And the poor guy was only 20 years old, and he was trying to protect his mom, supposedly," Patterson said.
Patterson watched as deputies removed the three family members from the home one by one, including the mother, who appeared visibly shaken, and Powell, who was led away in handcuffs before his injured father was brought out.
Another neighbor, Raquel Torres Casillas, expressed shock over the tragic breakdown of the family unit.
"We just feel bad because, you know, it was a family issue," she said. "It's sad because it's a family, you know, breaking up."
Legal options for prosecutors
Big picture view:
Legal analyst Michael Cardoza noted that the level of threat posed by the father will be central to the investigation.
If the mother's life was in actual danger, the incident could be considered a justifiable homicide, Cardoza said.
However, if her life was not in actual danger, that would change things.
"If it turns out her life was not in actual danger, but the son believed that she was in danger, that's what he believed, it's not a murder," Cardoza said. "It falls into the manslaughter range."
The victim's wife declined to comment on the record, stating she did not want to appear on the news.
What's next:
The Alameda County District Attorney's Office will review the case to determine whether to formally file charges against Powell.
Henry Lee is a KTVU crime reporter. E-mail Henry at Henry.Lee@fox.com and follow him on X @henrykleeKTVU and www.facebook.com/henrykleefan
The Source: Information in this story came from the Alameda County Sheriff's Department and interviews with neighbors of the family who lived in Castro Valley, Calif. on Parsons Avenue near Seven Hills Road. This story was reported by KTVU's Henry Lee.