A bomb threat forced the evacuation of the Manhattan Beach Studios Media Campus for over six hours on Tuesday in Manhattan Beach, Calif.

The sprawling 25,000 sq.-ft. facility, formerly known as Raleigh Studios in Manhattan Beach, Calif., was previously the home of Marvel Studios and was the filming location for such films as “Captain America: The Winter Soldier” and the upcoming “Avatar” sequels.

Police spokeswoman Stephanie Martin told Variety law enforcement officials received a call at 9:56 a.m. of a bomb threat that was phoned into the busy film and TV production center, forcing the evacuation of hundreds of employees.

Martin said that all staffers were immediately escorted from the building safely and that bomb sniffing dogs were brought into the massive complex, in addition to police forces from LAX, Los Angeles port police, Inglewood and Beverly Hills divisions before police finished the search without harm at 4:32 p.m.

There is no word on where the bomb threat originated.

“We have not only the investigation going on here but our detectives are in the background looking at phone numbers and getting search warrants and all that kind of stuff,” Martin said, adding that the anniversary of the Boston Marathon bombing had officials on high alert.

The police department taped off the 1600 block of Rosecrans Avenue for a quarter of a mile in most directions before the search was over.

Martin said the police department’s next task was trying to figure out who did it.