SAN DIEGO -

A 28-year-old man is behind bars today for allegedly prank calling his sister and saying there was a bomb in her car, which prompted authorities to shut down part of Interstate 15 and call in the bomb squad, according to the California Highway Patrol.

The woman called for help Thursday afternoon after she received an anonymous phone call from someone who claimed he had put a bomb in her vehicle. She then pulled into the center divide on northbound Interstate 15 south of Miramar Way and requested assistance, CHP officials said.

Responding CHP officers shut down both sides of the freeway -- the southbound lanes at Miramar Way, and the northbound lanes at state Route 52.

The San Diego Fire-Rescue Department's bomb squad and CHP explosive-detecting dogs were called in to examine the vehicle, however they later discovered the woman's brother, Victor Manuel Diaz of Bakersfield, was allegedly responsible for the threat.

Investigators tracked down Diaz and he admitted to making the prank call. Diaz was then arrested on suspicion of making the
threat and falsely reporting planting the explosive -- both felonies, according to the CHP and jail records.

Authorities opened the southbound lanes about 4:15 p.m. and the scene was declared safe and the northbound lanes were reopened shortly before 5:30 p.m.