Police have identified and arrested a man who allegedly stabbed and killed a young Black woman at an Oakland BART station on Sunday, ending a daylong manhunt, the San Francisco Gate reports.

Nia Wilson, 18, was at the MacArthur Station with her sister Lahtifa Wilson, 26, when they were allegedly stabbed by John Lee Cowell.

Nia Wilson died at the station and her sister was hospitalized.

“In my close to 30 years of police experience, it was probably one of the most vicious attacks that I’ve seen,” BART Police Chief Carlos Rojas said at a news conference on Monday.

Two other passengers reported to the police that they spotted Cowell on another BART train on Monday. He reportedly got on another train, where police were able to stop it and arrest him.

Rojas said that police don’t have a motive as of yet, but haven’t ruled out that it may have been a race-based attack.

Lahtifa Wilson told ABC-7 News that she and her two sisters were on their way home from a family event when they were “blindsided by a maniac.”

“I looked back, and he was wiping off his knife and stood at the stairs and just looked—and from there on, I was just caring for my sister,” she told the station. “I was in shock . . . I didn’t know I was cut because I was paying more attention to my sister. But he just stood there, like it was nothing.”

A vigil for Nia Wilson was held at the MacArthur BART station on Monday and hundreds attended.

Cowell’s arrest isn’t his first run-in with the law. In May 2016, he was convicted of felony second-degree robbery, according to court records obtained by SF Gate.