UPDATED: 11/28/2011 10:00 a.m.

CHICAGO (CBS) — Lake Zurich High School was put on lockdown for a few hours this morning after a suspicious package was found.

Police responded to the school, 300 Church St., at 6:30 a.m. However, investigators concluded there was nothing sinister in a package outside the school’s main entrance. It turned out to be just an empty camera case.

The school was re-opened by mid morning.

Students who had arrived at school early were held in the cafeteria while police and bomb squad officers investigated.

Class didn’t start until 8:30 on Monday, so parents were told to keep their children at home until authorities completed their investigation. Classes eventually began at 10 a.m.