Story highlights The man could bring a gun inside because he was a court employee, an official says

The employee shot himself in the head, the U.S. Marshals Service says

The shooter -- described only as a "middle aged white male" -- was taken to a hospital

A worker at the federal courthouse in Birmingham, Alabama, shot himself in the head Thursday, the U.S. Marshals Service said.

The man walked into the chief clerk's office at the Hugo Black U.S. Federal Courthouse "mumbling about a will. He then put a gun to his head and pulled the trigger," CNN affiliate WBMA reported, citing a source inside the courthouse. The FBI confirmed the source's report, WBMA said.

The shooter was able to bring a gun inside the building because, as an employee, he used "a different security entrance that has a different screening process," said Jill Ellis, administrative officer for the U.S. Marshals Service northern district of Alabama.

Described only as a "middle-aged white male," the shooter was taken to a local hospital after the incident. His condition was unknown, the marshals service said about 11 a.m. CT.

Birmingham police are leading the investigation into the shooting, according to the same federal agency. The incident posed "no threat to the federal courthouse," added the marshals service.