No one knows whether it was a Halloween prank or a genuine threat, but when campus officials searched entire campus for a bomb, none was to be found.

When University of California- Berkeley received an emailed tip Tuesday afternoon about a possible bomb threat, officers searched the buildings overnight to return empty-handed.

According to several local publications, Capt. Margo Bennett of UCPD said the tip was emailed to university's "Caltips" around 1 p.m. reporting an overheard conversation between two individuals about planting a bomb in the campus.

The university immediately notified the campus community saying that those who wish to leave the campus or the building could do so after informing their supervisor. At the same time, the university acknowledged majority of such threats are bogus, but appropriate measures are being taken to ensure campus community's safety.

The police give an 'all clear' notice by Wednesday morning as no explosive was found after meticulous searching.

University Vice Chancellor John Welton conveyed a notification to campus community through campus community, deeming the campus safe:

"This morning, the UCPD completed searches of the main and Clark Kerr campuses, as well as UC properties adjacent to the campus, and have recommended that all campus operations return to normal status.

We always encourage the campus community to use the opportunities available to share tips and information and remember that if they 'See Something, Say Something.' Threats to our campus safety are taken very seriously, so caution should be exercised when making casual remarks."

Berkeley is not the first university in recent months to receive such threats. UT-Austin, Texas A&M, Louisiana State, North Dakota State Universities, Hiram College in Ohio, Valparaiso University have previously been threatened by such anonymous bomb threats.

But only in the case of Louisianan State, was the culprit caught that too within a day.