Former Miami Dolphins offensive lineman Jonathan Martin, who has struggled with mental health issues after a 2013 bullying scandal that shook the NFL, was taken into Los Angeles police custody Friday after a threatening Instagram post on his account mentioned his former high school and two former NFL teammates.

Martin was being questioned by investigators after the post showed a shotgun and referred by name to the private Harvard-Westlake prep school in Los Angeles that he once attended, a law enforcement official told The Associated Press. The official was not authorized to discuss the matter publicly and spoke on condition of anonymity.

The post also included mentions of the Instagram usernames of former Miami Dolphins players Richie Incognito and Mike Pouncey and said suicide and revenge were the only options for a victim of bullying, the official said.

The Harvard-Westlake prep school was evacuated earlier Friday after officials were made aware of the post. It was not immediately clear whether Martin posted the photo himself and he was not under arrest Friday afternoon.

Martin left the Miami Dolphins midseason in 2013 after accusing teammates of bullying. An NFL investigation found that Incognito, Pouncey and teammate John Jerry engaged in persistent harassment directed at Martin.

Incognito was suspended for the final eight games and sat out the 2014 season before joining the Buffalo Bills.

The NFL's investigation also found that teammates threatened to rape Martin's sister, called him a long list of slurs and bullied him for not being "black enough." Martin is black and Incognito is white.

Martin, who underwent counseling for emotional issues after the bullying scandal, posted on Facebook in 2015 that difficulties in football led him to attempt suicide multiple times.

Martin, the son of two Harvard graduates, attended Stanford University. After he left the Dolphins, Martin played for the San Francisco 49ers and Carolina Panthers. He left the NFL in 2015.