SAN DIEGO -- A 300-pound man charged with fatally stabbing his mother — a veteran San Diego police detective — and his teen sister has an untreated mental illness that will be a key focus of his defense, his attorney said Wednesday.
The disclosure came as Brian Rockwell Williams, 24, pleaded not guilty to two counts of murder in the deaths. Prosecutors said he was arrested early Monday standing near a bloody knife and the body of his 18-year-old sister Briana.
Public defender Richard Gates told reporters outside court that Williams had a "schizophrenia-type" condition that left his mother conflicted because mentally ill people resist treatment.
"Think of the tension in this woman whose life has been dedicated to protecting the public, and yet she has a situation where she has someone in her house that poses a risk to the public and a risk to herself," he said.
Donna Williams, 52, joined the San Diego police in 1980 as a patrolwoman and spent most of her career in the child abuse unit. She lived in San Diego with the suspect and her daughter.
The detective was found dead in her daughter's bedroom with stab wounds to her stomach and throat, said Kristen Spieler, a San Diego County deputy district attorney.
"Having been with the department for 31 years, she clearly dedicated her life to protecting the lives of others and I think it's very likely she died trying to do the same thing," Spieler told reporters.
She declined to comment on what prompted the attack.
Neighbors awoke to a woman's screams and saw Briana struggling with her brother, and at one point hanging by her hands from a second-floor balcony outside her bedroom, Spieler said during the hearing.
Briana fell to the cement and her brother was seen calmly turning to climb through a window back into the home, the prosecutor said.
Police found Briana's nude body with about 20 stab wounds to her stomach and a slit throat.
Howard Williams, a San Diego attorney and the oldest of the five Williams children, sat in court during the hearing and later told reporters it was difficult to see his brother in handcuffs, wearing a jail uniform.
"We all were taught to support our siblings and our parents, and respect our parents, so, I, we, love our brother," he said. "We love our brother."
Howard Williams, 36, declined to comment on his brother's mental condition or on a June 30 disturbance in which police were called to the house but no arrests were made.
He told The San Diego Union-Tribune that the June 30 incident was a minor disturbance between him and Brian, declining to elaborate. His mother and sister were out of town at the time.
Their father, also a San Diego police veteran, died of cancer in 2007.
Howard Williams said his mother, brother and sister were the only three people living in the house in San Diego's Rancho Penasquitos area, but all the siblings resided in the San Diego area and visited often.
"We've always been a strong family, we're going to remain a strong family," he said.
Superior Court Judge David Szumowski ordered Williams held without bail. He faces a maximum sentence of life in prison if convicted of either murder charge.