The NFL player at the center of the Dolphins' bullying controversy appears to have used social media to threaten two of his former teammates. 

Jonathan Martin, who hasn't played in an NFL game since 2014, shared a picture of a gun on his verified Instagram page on Thursday night. The picture included the names of two of his former Dolphins teammates -- Mike Pouncey and Richie Incognito -- along with the names of two of his former high school classmates. Martin also specifcially named his former high school (Harvard-Westlake School) and the Dolphins in the disturbing photo. 

The picture also included the caption, "When you're a bully victim & a coward, your options are suicide, or revenge." 

Although there's a chance that Martin's verified page was hacked, the threat was serious enough that police in Los Angeles decided to shut down Harvard-Westlake on Friday due to the serious nature of the photo and due to the recent shooting attack at a high school Parkland, Florida, that left 17 dead. 

"With everything that happened in Florida, we're cautious," LAPD Officer Drake Madison told the Los Angeles Daily News. 

Harvard-Westlake high school also released a statement to explain why the school was closed on Friday. 

"Last evening, we learned of an Internet post that mentions Harvard-Westlake by name," the school said, via KTLA. "Out of an abundance of caution, and because the safety of our students, faculty, and staff is our top priority, we made the decision to close school [Friday]. We are working closely with law enforcement and will share more information when we are able."

ABC News has reported that Martin has been detained by police over the threat, although it's unknown if he'll be facing any charges. 

In what may or may not be a coincidence, the gun picture by Martin was released nearly four years to the day that the NFL's investigation on the Dolphins' bullying case was released. The Dolphins fired multiple people after the league released its report on Feb. 14, 2014. 

In the report, the league found that Incognito and Pouncey "engaged in a pattern of harassment directed" at Martin. Incognito was suspended for the final eight games of the 2013 season and didn't play in the NFL at all in 2014. As for Martin, he was traded to the 49ers in March 2014 and was out of the NFL completely by 2015. 

The now retired offensive lineman has been battling depression and even admitted in 2015 that he attempted suicide while playing for the Dolphins. In a May 2016 interview, Martin said there would never be any reconciliation with Incognito.  

"I have no desire to ever see or talk to him," Martin told USA Today at the time. "That's in the past. I don't know what his thoughts are and I don't really care, honestly."