ANTIOCH -- Students have been cleared to returned back to class at Deer Valley High School following a bomb threat from an anonymous caller this morning.

The evacuation of the southeast Antioch campus -- the second time in as many days -- was lifted around 12:40 p.m., Principal Ken Gardner said via a robocall to parents.

Antioch police responded to the bomb threat and conducted a thorough search of the campus with campus staff and nothing was located, Sgt. Tony Morefield said.

Today's case appears to be unrelated to Monday's bomb threat, but both incidents are still under investigation, Morefield said.

Gardner said students were moved to the athletic fields off campus around 10:45 a.m. today while police scoured the campus to search for explosives.

In an automated call and email to parents, Gardner said they should stay away from the school.

On Monday, the school received an anonymous phone call around 1:45 p.m. warning of the threat of a device "in an undetermined location" on campus, before the caller abruptly hung up. Students were moved to nearby athletic fields for more than an hour.

Contact Paul Burgarino at 925-779-7164. Follow him at Twitter.com/paulburgarino.