Three employees at Istrouma High were placed on leave as an investigation continues into a gun that discharged inside a classroom last week, after a student managed to slip past metal detection.

Taylor Gast, a spokeswoman for the East Baton Rouge Parish school system confirmed that the three employees — the school’s principal, a teacher and an office clerk — were placed on leave due to the investigation, which she described as standard procedure, but said Principal Cleotha Johnigan returned to school Tuesday. All three went on leave at some point after Wednesday, the day when the incident occurred, Gast said.

Marcus Washington, 18, a senior at Istrouma and a prominent member of the school’s basketball team, admitted to bringing the gun to school last Wednesday, telling authorities that the gun went off when he tried to adjust it in his pants. The gun, a Glock 45 modified with a switch that converts into an automatic weapon, was later found in the ceiling of a school bathroom. There were no injuries.

East Baton Rouge Parish Supt. LaMont Cole said Washington arrived late for school that day, was flagged by the metal detector, but that a school clerk opted not to check him or his backpack for a weapon because of the possibility it was a false reading and because Washington was considered a good student who was popular due to his prowess at basketball.

Washington was booked in parish prison on multiple counts, including carrying a firearm on school property, negligent carrying of a concealed handgun; illegal use of weapons and illegal possession of stolen firearms. Washington also has been recommended for expulsion from school due to Louisiana’s zero tolerance law.