A woman who formerly coached the Thousand Oaks mass shooting suspect on his high school track team says he aggressively assaulted her but that her co-workers persuaded her not to report it.

Former Newbury Park High School track coach Dominique Colell told CBS Los Angeles that when she saw the news of the mass shooting the killed 13 people, including suspected gunman Ian David Long, she recognized the shooter, who is believed to have taken his own life, as a former member of her high school track team who assaulted her after she discovered an unattended cell phone during track practice and was trying to track down its owner.

“Ian came up and started screaming at me that was his phone,” Colell told the news station. “He just started grabbing me. He groped my stomach. He groped my butt. I pushed him off me and said after that — ‘you’re off the team.’ ”

“He attacked me. He attacked his high school track coach,” she said. “Who does that?”

Colell told CBS Los Angeles that she declined to report the alleged sexual assault because fellow coaches convinced her it may derail Long’s plans to join the Marine Corps.

“I should have reported it then,” Colell said, adding that Long’s behavior was a concern before he joined the military, after which a neighbor speculated that he may have been suffering from PTSD.

“There are hundreds of thousands of people with PTSD,” said Colell. “They don’t go around shooting people. This kid was mentally disturbed in high school. There were signs and the administration knew it.”

It is unclear exactly when the alleged attack took place. A former high school classmate of Long’s told CNN that Long appeared to have anger issues in high school. But friends who knew him more recently said they were shocked to learn he was behind the gun massacre that killed 11 civilians, some of them college students, and a veteran police officer a year away of retirement. Authorities said Long was found dead at the scene inside the Borderline Bar and Grill, likely from a self-inflicted gunshot wound.

Investigators have not yet determined a motive for the deadly mass shooting.

[Feature image: CBS Los Angeles video screenshot]