BATON ROUGE — State Police is investigating who called in a bomb threat to its headquarters and halted operations Sunday morning. 

A source told WBRZ Sunday morning that someone had threatened the State Police headquarters on Independence Boulevard.

Lt. Jared Sandifer said LSP received the threat through a phone call, but could not confirm what time it came in, and multiple agencies would be performing a sweep of every building on the campus out of an abundance of caution. 

"We do have employees here, we do believe that they are safe, it is controlled access," he said, "So there are people in the building but they have all been notified of what's going on. We have told other employees not to come to the campus until it is swept."

In addition to State Police, the Baton Rouge Police Department and the Baton Rouge Fire Department had people stationed outside.

Officials said they did not find anything in the sweep of the building. 

The all-clear was given around 11:30 a.m. and the campus was re-opened for all employees. 

This threat is still under investigation and no further information was available on who called the threat in or why.