Jonathan Martin, the former N.F.L. offensive lineman who was at the center of a bullying scandal in 2013, was detained by the police after posting a seemingly threatening message on social media.
A photograph he posted on Instagram showed a rifle and included a message that said bullying victims had only two choices, suicide and revenge. It included the name of the private high school he attended in Los Angeles, prompting officials there to shut the school on Friday.
“When you’re a bully victim & a coward, your options are suicide, or revenge,” the post read.
The incident comes less than two weeks after a former student at Marjory Stoneman Douglas High School in Parkland, Fla.