Updated

A worker who killed himself inside an Alabama federal courthouse Thursday went through an employee entrance to avoid a security check that could have caught the gun, officials said.

The U.S. Marshals Service said the worker used an access card to enter the Hugo L. Black U.S. Courthouse in Birmingham. The card system is being used at times while renovation work is done on the main entrance.

The man, identified by authorities as building services director David Lee Williams, 50, of Birmingham, did not walk through metal detectors that are staffed by security officers to prevent weapons from entering the building, the Marshals Service said.

Police Sgt. Johnny Williams said the worker shot himself once in the head in a first-floor clerk's office. It was unclear how open or public that area of the office is, and officials would not elaborate Thursday. No one else in the building was threatened, Williams said.

Officials said courthouse procedures were under review after the shooting, but they declined to discuss details, citing security concerns.

Courthouse business was delayed briefly after the shooting, but the building remained open.