DEERFIELD BEACH, Fla. – A pistol-packing Marjory Stoneman Douglas teacher who said he'd be willing to be trained to carry a gun to protect the high school faces a criminal charge after he left his Glock 9mm in a public restroom where it was later fired by an apparently intoxicated homeless man, according to the Broward Sheriff's Office.

Science teacher Sean Simpson –- who was at Marjory Stoneman Douglas High School when 17 people were killed in a mass shooting – told deputies he accidentally left the gun in a stall at the bathroom at the Deerfield Beach Pier during a visit to the beach Sunday. While going back to retrieve it, he heard a gunshot and once back inside the bathroom, saw 69-year-old Joseph Spataro holding the gun. Simpson then snatched the gun out of Spataro's hands, deputies reported.

Simpson, 43, was arrested and charged with failing to safely store a firearm, a second-degree misdemeanor punishable by a maximum of 60 days in jail. He posted a $250 cash bond.

Spataro, who told deputies he'd fired the gun to see whether it was loaded, was charged with trespassing and firing a weapon while intoxicated. The bullet fortunately did not strike anyone and was later found inside the concrete block structure by deputies, who were alerted to the situation by a witness running from the scene.

"There was a reasonable likelihood that the firearm could have ended up in the hands of a child or the discharge of the firearm could have wounded another person or child," deputies wrote in the arrest report.

Simpson, who supervised student activist Emma Gonzalez on a science project and appeared in a short documentary made by David Hogg before the shooting, has been a supporter of Stoneman Douglas students' gun control efforts and attended the March For Our Lives protest in Washington D.C. on March 24.

"I was running from the sound of gunfire .. in a high school I felt safe in," Simpson said during an MSNBC interview a week after the Feb. 14 shooting. "That's not OK, that never should be a thing that could happen. .. These kids are demanding action, they're going to cause change."

When asked about the prospect raised by President Donald Trump of arming teachers, Simpson seemed open to the idea.

"I know there are some of us that are willing to take the training if it was offered and probably be another line of defense," he said. "But again that is a complicated subject and I'm not sure if it's the answer. I think it's easier to get these types of weapons out of the hands of people that aren't meant to do anything but kill."

When reached on the telephone after his arrest, Simpson said he could not comment on the criminal case, though he did say he did not believe it constituted a violation of school board rules. He continues to teach at Stoneman Douglas and a Broward County School Board spokeswoman said the district is not expected to take any professional action against him in the case.