(CNN) - A former NFL player who attended a prestigious private high school in Los Angeles was detained by police Friday in connection with a social media post that prompted the closure of the school due to security concerns, according to two law enforcement sources familiar with the matter.
Jonathan Martin, who graduated from Harvard-Westlake in 2008 and went on to play as an offensive lineman for the Miami Dolphins and San Francisco 49ers, was being questioned by LAPD detectives about the post, the sources confirmed. The sources requested not to be named due to the sensitive nature of the ongoing investigation.
The image in question depicted a black shotgun with the words #HarvardWestlake superimposed over it and shotgun shells scattered around the weapon.
There was also a reference to "#MiamiDolphins" on the gun. A message to the side of the weapon read: "When you're a bully victim & a coward, your options are suicide or revenge"
The image was circulated among students at Harvard-Westlake and was shared with CNN. School officials said the image had been attributed to a former student, but did not identify the person.
LAPD officials declined to name the person who had been detained, but said that person is believed responsible for the post.
Martin was bullied by Dolphins teammates in 2013, according to an independent report commissioned by the NFL. At least one of the suspected bullies was apparently referenced in the post.
Martin referred to his "white private school conditioning" as a reason he tolerated verbal abuse, according to a 2014 report issued in the wake of the NFL bullying scandal.
An LAPD spokesperson described the investigation into the social media post as "still going, still fluid."
Officials at Harvard-Westlake notified parents and students of the situation on Friday morning:
"Very late last night, we were made aware of a disturbing social media post that mentioned Harvard-Westlake by name," read a message from the school's president, Richard B. Commons. "The safety of our students, faculty, and staff is always our primary concern. So, out of an abundance of caution, we made the decision to close school today."
The message added that the school's private security team was working with LAPD officers, who were present on campus. "With these precautions in place, we believe there is no imminent threat to our campuses or our school community," Commons said.
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