New details have emerged in the case of a former NFL star and his cryptic Instagram post in which he threatened four people and caused his former high school to shut down.

According to court documents obtained by TMZ Sports, Jonathan Martin – who played for the Miami Dolphins and San Francisco 49ers – was arrested by police on February 23 was arrested with a cache of weapons.

When officials searched his car, they found a loaded 12-gauge shotgun, a large knife, an ax and a cell phone. A second shotgun was found at his parents’ home.

Martin, a former offensive lineman, was placed on a 72-hour psychiatric hold because officials believed he was a possible danger to himself and others. 

Additionally, Martin’s girlfriend, who spoke with officials, said the former player had been making suicidal remarks for a month and had been ‘writing on the walls’ of his home.

Investigators also spoke with the two former high school classmates Martin tagged in his cryptic Instagram post, both of whom said Martin had been sending them disturbing Facebook messages starting in 2016. 

The news comes just a week after the prestigious Harvard-Westlake School filed the workplace violence prevention restraining order again Martin, a former student, ESPN reported.

Martin, 28, attended Harvard-Westlake, an elite private school costing $38,000 a year and popular with celebrities, before going on to Stanford. 

The restraining order prohibits Martin from entering the campus and requires him to stay 150 yards away from school properties and facilities.

The threat in question, posted to an Instagram account believed to belong to Martin, read ‘When you’re a bully victim & a coward, your options are suicide, or revenge.’

The post also included an image of a shotgun and shells, with four social media accounts tagged and hashtags for Harvard-Westlake and the Miami Dolphins.       

Among the four names tagged were former Dolphins teammates Richie Incognito and Mike Pouncey. 

Martin accused Incognito and Pouncey of bullying following racially-charged incidents in 2013. 

 Incognito was suspended by the team for three months after Martin left the club midway through the 2013 season.

Incognito left voicemails on Martin’s phone calling him a ‘half-n****r piece of s**t’, threatening to slap his mother and even making death threats against Martin.

The current Buffalo Bills player also joked about ‘running a train’ on Martin’s sister, and made other crude remarks about her. 

Martin, who hasn’t played in the NFL since 2015, reportedly checked into a hospital for emotional distress over the incident, and returned to his parents home in California.

He ultimately quit the team and debated giving up on his career, feeling such psychological duress that he said he twice considered committing suicide. 

In November that year, Incognito was suspended for ‘conduct detrimental to the team.’ 

Also tagged in the Instagram post was sports agent James Dunleavy, VP Basketball at Independent Sports & Entertainment and TJ Taylor, a top executive at an exclusive dating app – both appear to be former students at Harvard-Westlake.

It’s not clear whether Martin also suffered from bullying at Harvard-Westlake. 

Neighbors of Martin at the upscale, modern apartment building in West Hollywood where he lives, were stunned at the news. 

‘He seemed very quiet and pleasant when I would run into him in the elevator or the garage,’ one woman – who lives on the third floor, the same as Martin’s – told DailyMail.com.

‘He would say, ‘hey’ and that was it. He wasn’t very talkative. 

‘He’s real big but he didn’t strike me as somebody who was aggressive or violent. He was like a gentle giant.’