This morning, Wilson Senior High received an anonymous caller with a scary tip: there was a gun in the building.

Wilson administrators put the entire school on lockdown. School security—with D.C. Police Department officers observing-did a sweep of the lockers on the third floor. The tipster said the gun would be found on that floor.

“They did a check of the lockers and the only thing that turned up was a Super Soaker,” says Mafara Hobson, press secretary for Chancellor Michelle Rhee. “We don’t have any proof that it’s a prank call but…my gut feeling is that it was a prank call.”

Students remained in their first period class, Hobson says, while the officers conducted their search.

This lockdown follows an incident at Wilson last Monday in which security guards thought they saw the outline of a gun in a student’s backpack when it went through the metal-detector-x-ray-machine. Security guards found nothing in the backpack, Hobson says. But they ended up searching the entire school just to be sure. Again, they found no guns at Wilson.