WASHINGTON — Potomac High School in Oxon Hill, Maryland, was on lockdown for nearly two hours after a former student was seen trespassing on the school’s campus Tuesday morning.

Prince George’s County Police say a current student was spotted talking with the trespasser, and while police questioned the student they recovered a gun. That student is now in custody.

The school was put on lockdown at 9:45 a.m., however police say the former student was spotted leaving the campus. The lockdown was lifted just before 11:45 a.m.