Check out the local report on CNN affiliate WBAL-TV in Baltimore, Maryland.

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.

Police moved in and closed off the floor after the shooting, which occurred shortly after 11 a.m. About 1:30 p.m., after nearly two and a half hours with no contact with the gunman, officers used a robot to peer into the room and when it was determined there was no movement, police entered to find the suspect and his mother dead, Bealefeld said. No officers reported hearing gunshots, but both mother and son had single gunshot wounds to their heads, he said.

"At this point we are treating this case as a murder-suicide," Bealefeld said.

Police identified the mother as Jean Davis, age 84, and her son as Paul Warren Pardus, age 50, of Arlington, Virginia. Pardus had no prior criminal record beyond traffic violations, police spokesman Anthony Guglielmi said.

The doctor, whose name was not released, was rushed to surgery for an abdominal wound and is expected to survive, Guglielmi said.

"He's in the best place he could ever be," Guglielmi said, referring to the hospital.

Bealefeld initially identified the gunman as Warren Davis. Hospital officials said they could not disclose any details about what illness afflicted the gunman's mother, citing federal privacy laws.

Johns Hopkins Hospital, which first opened in 1889, is part of a $5 billion medical system, according to its website. The 982-bed facility has consistently earned the top spot in U.S. News & World Report's annual rankings of more than 4,800 American hospitals, placing first in five medical specialties, among other things.

Harry Koffenberger, the hospital's security chief, said the roughly 80,000 visitors who come to the hospital each week are issued wristbands. Only "high-risk" patients get screened with hand-held magnetometers, he said.

"We have over 80 doors, loading docks and emergency exits on these campus buildings," Koffenberger said. "So to put a magnetometer at 80 doors, and the required armed force that would need to be staffing the magnetometers, is not realistic."

Authorities evacuated part of the hospital after the shooting, and Bealefeld said the facility's security plan "worked as designed" to protect patients, staff and visitors. The hospital "asked employees, visitors, patients and caregivers to stay in rooms or offices until further notice" restricted access to the main hospital building after the shooting, it said in a statement.

Earlier, police said officers shot and killed the gunman, but later said that account was incorrect.

CNN's Rachel Streitfeld contributed to this report.