Read more about this story from local CNN affiliate WJLA
Baltimore, Maryland (CNN) -- A gunman who wounded a doctor, killed his mother and turned the gun on himself at Johns Hopkins Hospital in Maryland was upset with his mother's unsuccessful surgery, a relative said.
Paul Warren Pardus, 50, 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.
According to the Baltimore Sun, Pardus shot Dr. David Cohen before retreating to his 84-year-old mother's room.
Ronald Alvin Gibson, Pardus' half-brother, told CNN affiliate WJLA that the elderly woman could have been paralyzed after a recent surgery.
"I talked to him Sunday," Gibson said, referring to Pardus. "He said her operation was not successful, that it had not turned out the way the doctor said it would. I just wanted her to get well and come home soon. He wanted that also. He said that she may not be able to walk again."
Both mother and son were found with single gunshot wounds to their heads, police said.
"At this point, we are treating this case as a murder-suicide," Bealefeld said Thursday.
Police identified the mother as Jean Davis. Pardus had no prior criminal record beyond traffic violations, police spokesman Anthony Guglielmi said.
Cohen, who was shot in the abdomen, is recovering in the hospital, officials said.
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.
CNN's Rachel Streitfeld contributed to this report.