Martin originally shared a photo of a shotgun and bullets with the caption "When you're a bully victim and a coward, your options are suicide or revenge".
According to an online file, the Los Angeles District Attorney's Office has filed five criminal charges against Martin. The image included references to the Dolphins, and Mike Pouncey and Richie Incognito - his former Miami teammates who were part of a 2014 National Football League investigation that determined Martin was victimized by a "pattern of harassment" directed toward him.
The South Florida Sun-Sentinel reported that Martin checked into a mental facility on the day of the Instagram post, where he was detained. Furthermore, the report states there is now a warrant issued for Martin's arrest.
Harvard-Westlake School - where Martin graduated from in 2008 and was shut down on February 23 in response to the post - and two other individuals also were referenced in the image.
Brother of Parkland shooter arrested for trespassing at Stoneman Douglas high
The former deputy has been called a "coward" for staying outside the school while the shooting took place inside. Cruz is being held without bond at the Broward County Jail, where he's segregated from other inmates.
Rubenstein said he did not know details about the charges, but a law enforcement source who spoke on condition of anonymity said they were connected to last month's social media post that named the school. TMZ first reported on Monday that there's a warrant out for Martin's arrest.
Incognito was at the center of the bullying scandal which enveloped Martin, and the Dolphins in 2013.
A day later when Martin was arrested, police found a loaded 12-gauge shotgun, knife, and ax located in his auto.