Baltimore, Maryland (CNN) — A man distraught about his mother’s health shot and wounded a doctor at Baltimore’s prestigious Johns Hopkins Hospital on Thursday before killing his mother and taking his own life, police said. The gunman was getting an update on his mother’s medical condition “when he became emotionally distraught” and pulled a pistol out of his waistband, Baltimore Police Commissioner Frederick Bealefeld said. He shot the doctor, then retreated to his mother’s room, Bealefeld told reporters. Bealefeld identified the gunman as 50-year-old Warren Davis, and the mother as Jean Davis. But police later said “Warren Davis was an alias,” and the gunman’s real name was unknown. They continued to identify the dead woman as the gunman’s mother. Hospital officials said they could not disclose any details about what illness afflicted the gunman’s mother, citing federal privacy laws. Police moved in and closed off the floor shortly after the 11 a.m. shooting. About 1:30 p.m., officers moved into the room to find the man and his mother dead from single gunshot wounds to the head, Bealefeld said. The doctor, whose name was not released, was rushed to surgery for an abdominal wound and is expected to survive, police spokesman Anthony Guglielmi said.

Police in Maryland are responding to a hostage situation after reports that a man with a handgun entered the Discovery Channel headquarters building in Silver Spring and fired at least one shot. An official with the Montgomery County Police Department confirmed to Fox News that a man with an explosive device is holding at least one person hostage in the lobby of the building. A Discovery employee reportedly told WJLA-TV that the building, located in suburban Washington, D.C., was on lockdown. The employee also said she thought she had heard five or six gunshots. Dan Friz, a spokesman with the Montgomery County Police Department, reportedly told the station that a tactical team is trying to communicate with the gunman. Friz said police were initially dispatched to the building after a report of shots fired at approximately 1 p.m. The suspect, identified by police as an Asian male, has “some sort of device on him that may be explosive in nature,” Friz said. Some witnesses reported that the man fired a shot before declaring, “Nobody is going anywhere,” according to police.