HOUSTON, Jan. 13 -- A "potentially explosive device" was found Monday on a high school campus in the U.S. state of Texas, prompting evacuation, and was later proved to be a zip gun, local media reported.

Officials with the Seven Lakes High School in Katy in southeastern Texas reported on Monday morning a suspicious backpack on the campus, local media KHOU reported.

All the 3,000-some students were evacuated, and police and a bomb squad were called to the scene.

Authorities found hours later that the suspicious device in the backpack was a zip gun, a device that can propel an object to cause harm. Devices like this are often made with a pipe and can fire nails, according to the report.

A male student suspect was then taken into custody. His motive of bringing the gun to the campus is unknown. Officials said charges are pending for him.

The Seven Lakes High School remained locked on Monday evening and reportedly will resume its normal schedule Tuesday.