BALTIMORE – A man who became distraught as he was being briefed on his mother’s condition at Johns Hopkins Hospital pulled a gun and shot the doctor Thursday, then killed his mother and himself in her room at the world-famous medical center, police said.

Baltimore police Commissioner Frederick H. Bealefeld III said the doctor had been talking to 50-year-old Warren Davis just after 11 a.m. when he “became emotionally distraught and reacted … and was overwhelmed by the news of his mother’s condition.” Bealefeld said he did not know what the woman was being treated.

Davis then pulled a semiautomatic handgun from his waistband shot the doctor once in the abdomen, the commissioner said. The doctor collapsed outside room 873 of the Nelson building, where Davis’ mother, Jean Davis, was being treated. Warren Davis then holed up inside his mother’s room for more than two hours during a standoff with authorities.

When officers made their way to the eighth-floor room, they found Warren Davis dead on the floor and his mother dead in her hospital bed.

Two Hopkins employees said the physician who was wounded is Dr. David B. Cohen, an assistant professor and orthopedic surgeon. The employees asked to remain anonymous because they are not authorized to discuss the matter. Police said the doctor underwent surgery and was expected to survive.

Michelle Burrell, who works in a coffee shop in the hospital lobby, said she was told by employees who were on the floor where the doctor was shot that the gunman was angry with the doctor’s treatment of his mother.