AURORA, Colo. -

Students are returning to an Aurora middle school a day after being evacuated because of the discovery of a pipe bomb on campus.

Classes were resuming at Mrachek Middle School Tuesday as police search for the suspects who tried to set off the device on Saturday night.

Security camera captured the suspects lighting the bomb in an alcove between two buildings. The device just burned and didn't detonate.

The school is increasing security as a result.