He has a long criminal history and at one point police arrested him at a BART station for a robbery case.
BART riders are ultimately the ones who located Cowell Monday leading to his arrest by BART police at the Pleasant Hill Station. It's unclear how he got back into the system, but ABC 7 News Reporter Katie Utehs spoke with a woman who saw him at the Coliseum BART Station platform and he rode her train.
VIDEO: 'Remember Her' A tribute to Nia Wilson
"I don't know he just gave me a feeling in my stomach. I don't know. I don't know, I guess call it intuition," recalled Jaunice Reed about the moment she spotted Cowell.
Reed walked by the suspicious looking man on the platform and recorded video Monday evening thinking the man could be the wanted murder suspect.
"I sent the video to my husband who was waiting for me at MacArthur BART and he was like, 'No, I don't think that's him, you're just tripping' because maybe we're just looking at everyone thinking that's him, that's him," said Reed.
VIDEO: This is the moment the BART stabbing suspect was arrested
Reed captured the beginning of the end of a nearly daylong manhunt for the man suspected of killing Nia Wilson and injuring her sister Latifah on Sunday night.
At just 27 year's old Cowell's adult criminal history started at 18. It includes misdemeanor drug offenses, obstruction of a peace officer, and assault.
In 2016 at the Lucky's in El Cerrito he was accused of shoplifting.
VIDEO: Oakland BART stabbing victim recalls horrific attack that killed sister
"The loss prevention officer attempted to confront him, detain him and that's when the defendant reacted with a gun, a handgun," said Scott Alonso, Contra Costa County District Attorney's Office spokesperson.
It turned out to be a toy gun, but Cowell also had a boxcutter knife. Police caught him at the El Cerrito BART station. He served his sentence in state prison and got paroled in May of this year. Contra Costa prosecutors say he's been mentally evaluated in the past.
"He was evaluated by a doctor in the robbery case in October of 2016. he was found competent to stand trial," said Alonso.
Reed watched Cowell closely on the train. He sat behind the conductor. At the 12th Street BART station she says two boys approached him. She says he ran off, but not before saying the N-word.
VIDEO: What we know about deadly stabbing at Oakland's MacArthur BART station
"What I heard out of his mouth was 'something, something, something' I couldn't hear the first three words 'last night n-----,'" said Reed.
When the train stopped at MacArthur Station the boys notified BART officers on the platform. Then at Pleasant Hill an uneventful arrest was captured by another BART passenger.
We asked Reed how Cowell appeared. She said he avoided her camera.
"Evil if anything, but not mentally ill," said Reed.
Cowell is being held in the Santa Rita jail. He's scheduled for his first court appearance Wednesday morning.
Go here for full coverage on the stabbing at Oakland's MacArthur BART station that took the life of 18-year-old Nia Wilson.
CONTINUING COVERAGE ON DEADLY BART STABBING:
- What we know about deadly stabbing at Oakland's MacArthur BART station
- 'Remember Her' A tribute to Nia Wilson
- Here's how you can help the family of BART stabbing victim Nia Wilson
- Chilling dispatch call describes terrifying fatal MacArthur BART stabbing
- 'He was wiping off his knife': BART stabbing victim recalls horrific attack that killed sister
- Heartbroken father demands justice after daughter stabbed at BART station
- 'Stand down': BART stabbing victim's godfather makes plea to black community
- TIPS: How to stay safe on BART
- Bart releases info on pair of homicides