By LORIN ELENI GILL and OLGA R. RODRIGUEZ
OAKLAND, Calif. (AP) -- Prosecutors will seek a life sentence against a parolee charged with murder and attempted murder in the unprovoked stabbing of two young women at a subway station, a Northern California district attorney said Wednesday.
Alameda County District Attorney Nancy O'Malley said authorities continue to investigate whether John Cowell, 27, was motivated by racial hate when he killed Nia Wilson, 18, and wounded her sister, Letifah Wilson, 26.
The women are black and he is white.
"Having sat down with the family, this is the worst time in their life, and my heart is broken for them and also for our community at large," she said after the hearing. "It has shaken the community, it has shaken all of us."
Cowell did not enter a plea in a brief hearing and his arraignment was held over until next month. The courtroom was packed with about two dozen members of Wilson's family. One woman wailed after the hearing was over.
The young woman's death Sunday prompted a vigil that later swelled into a crowd of about a thousand that marched in downtown Oakland across the bay from San Francisco.
A panel hid Cowell from view but courtroom artist Vicki Ellen Behringer could see him. He looked down for most of the hearing, she said and at one point, he had a slight smile. Cowell had a tattoo on his chest and a bandage on his forehead, she said.
Cowell's lawyer, George Arroyo, slipped out the back door after the hearing and did not respond immediately to a request for comment.
Cowell was arrested Monday night on a Bay Area Rapid Transit train about a dozen miles (19 kilometers) from the MacArthur station where the women were attacked.
Authorities haven't released a motive for the attack but Cowell's family told KRON-TV in a statement that he has suffered from mental illness "most of his life." Cowell had been in and out of jail without receiving proper treatment, the family contended.
Nia's father, Ansar Muhammad, said Wednesday he thought claiming mental illness was "an excuse" and he felt his daughters were attacked because they are black.
"I think it's an excuse. I hate to say that, but, you know, why would you choose two black girls?" Muhammad said at the courthouse before Cowell's appearance.
Muhammad said Nia was going to graduate "with very high honors" from Dewey Academy in December and planned to join the military.
"I should be planning her graduation, not her funeral," he said.
Records indicate Cowell recently served two years for second-degree robbery and also had convictions for battery, being under the influence of a controlled substance and assault with a deadly weapon, the East Bay Times reported.
Cowell was diagnosed with bipolar disorder and schizophrenia, the family said.
He was released from the Atascadero state mental hospital in May but "there was not a place for him to go with most of the mental institutions being shut down," the family said, adding that "the system has failed in this instance."
"We had to get a restraining order at one time as well for our own protection. He was living on the streets without the proper treatment," the family said. "This is in no way an excuse for this senseless and vicious attack."
Cowell's mother, Anne Cowell, is serving a three-year sentence for setting fire to a transitional housing shelter in Santa Rosa, the Sonoma County Sheriff's Office said.
California Department of Corrections and Rehabilitation spokeswoman Vicky Waters said Cowell had been under "active parole supervision and had no arrest warrants."
She said the agency is conducting a review and also cooperating with BART and local law enforcement in their investigation.
Cowell's family said it was "heartbroken" and mourning for the victims' family.
"This horrific tragedy never should have happened," the statement said.
BART police said they were also investigating the death of a homeless man who was attacked at a subway station the day before Nia Wilson was fatally stabbed on a transferring platform.
BART police late Tuesday released images of a man who allegedly punched 47-year-old Don Stevens at the Bay Fair station on Saturday.
The suspect hit Stevens in the side of the head with a closed fist. Stevens fell and struck his head and died at a hospital Sunday, they said.
Rodriguez reported from San Francisco.