Via NPR: 

Sean Simpson, a teacher at Marjory Stoneman Douglas High School, has spoken in favor of gun control efforts and said he might be open to the idea of carrying a gun in class. Now, he has been arrested after leaving his Glock 9 mm pistol in a bathroom over the weekend.

Simpson told the authorities that he had forgotten the loaded weapon in a stall in the bathroom at the Deerfield Beach pier. But before he could retrieve the pistol, the Sun-Sentinel reports, "a drunk homeless man found it and fired it, according to an arrest report from the Broward Sheriff's Office."

No one was injured in the incident, but Simpson, 43, was arrested and charged with failing to safely store the weapon. He posted $250 bond, according to local media.

Read more here.