HARTLAND, Wis. -

Police will be patrolling the neighborhood around a Hartland elementary school as students head to class.

Officers armed with assault rifles searched a 3-acre wooded area around Hartland North Elementary Thursday afternoon after two students reported seeing a man in a dark hooded sweat shirt holding a rifle-size weapon. Police Chief Robert Rosch says the two 7-year-old boys heard a loud bang and ran back into the school.

The building was locked down. Officers say they didn't find anything suspicious. Superintendent Glenn Schilling tells WISN-TV it's better to "err on the side of caution."