Former Miami Dolphins and San Francisco 49ers offensive tackle Jonathan Martin reportedly posted a photo of a gun and ammunition on his Instagram story Friday, prompting his former high school to close, according to the Los Angeles Times.

ABC reported on Friday afternoon that police took Martin into custody after he was found in possession of a knife, shotgun and ax, according to TMZ Sports, and reported Saturday morning that he is being held in a mental health facility.

The photo was captioned with “When you’re a bully victim & a coward, your options are suicide, or revenge.” Former teammates Richie Incognito and Mike Pouncey, as well as two others, were tagged in the post.

Former Dolphins OL Jonathan Martin with some seriously disturbing stuff on his IG story... pic.twitter.com/NaJ8a0BXze — Nick Brown (@NickyBeaster) February 23, 2018

The Instagram account has no profile photo, but is a verified account with 347 followers.

Incognito and Pouncey were named as part of a report into a bullying scandal when they were teammates with Martin on the Dolphins, along with John Jerry. The harassment reportedly started in 2012 during Martin’s rookie year with the team. He left the team in October of 2013 after an incident in the team’s cafeteria.

Harvard Westlake High School in Studio City closed on Friday because of a “security risk.” The Los Angeles Times confirmed that it was because of Martin — a 2008 graduate of the school.

From the Times:

The image, which showed the weapon and referenced revenge and suicide as the only options for a victim of bullying, was posted to a verified Instagram account belonging to Jonathan Martin, the former Dolphins’ offensive lineman who retired from the league after he accused teammates of bullying in 2013, according to three sources with knowledge of the situation.

The paper also wrote in 2015 that “[Martin] expressed being uncomfortable as ‘one of just a handful of minorities in elite private schools.’”

Harvard Westlake officials said they were unaware of Martin’s feelings at the time he was at the school. Its head of athletics, Terry Barnum, told the Los Angeles Times in 2015, “Obviously his childhood was a difficult time. We supported him and support him now. We are always looking for ways to be more inclusive and more diverse. That is a foundational principle of our school.”

TMZ later reported that Martin was is possession of a knife, a loaded gun, and an ax when arrested.

Martin hasn’t been in the NFL since 2014, when he appeared in 15 games and started nine for the 49ers.