Boston mourns surgeon killed by son of deceased patient

The emblem flag at Boston's Brigham and Women's Hospital was lowered to half staff Wednesday as the hospital and city mourned the brutal murder of heart surgeon Michael Davidson.

Boston police were trying to determine why the son of a former patient walked into the hospital's Shapiro Cardiovascular Center on Tuesday and fatally shot his mother's doctor.

Police said Stephen Pasceri, 55, specifically asked for Davidson, 44, the director of endovascular cardiac surgery. Pasceri then shot Davidson twice outside an exam room.

Davidson, the married father of three, died hours later. Pasceri, who was married with four children, was found at the scene, dead of an apparent self-inflicted gunshot wound.

"Everything seemed to be going really well. I have no idea why he snapped like this," Marguerite Joly, Pasceri's sister, told the Boston Herald.

Joly told the newspaper the family had a good relationship with Davidson while their mother was a patient. She said she did not know why her brother would blame Davidson for their mother's death.

"He was a great guy," Joly told the Herald. "He was an upstanding citizen. We can't even wrap our brains around this. There was no indication whatsoever that he would ever do anything like this. He loved his mom, and he loved her very much. He appeared to be handling her death well.

"This was not a bad, evil man," she said. "Something happened, and I don't know what."

Millbury neighbor Neal Cameron, 48, told the Herald Pasceri was a "nice guy" who was often walking his dog, a Newfoundland named Moses.

"It's just a shock that something like this would happen," he said.

Pasceri "had some issue" with medical treatment of his mother, Marguerite Pasceri, who died Nov. 15, police Superintendent Robert Merner told the Boston Globe.

Davidson, a surgeon at Brigham since 2006, was also an assistant professor at Harvard.

Wellesley neighbor George Corbett, 61, told the Globe Davidson was "a very friendly man. When he (was) walking in the neighborhood, he would always say hello."

"Dr. Davidson was a wonderful and inspiring cardiac surgeon who devoted his career to saving lives and improving the quality of life of every patient he cared for," the hospital said in a statement.

Boston Mayor Martin Walsh said he was "deeply saddened" by Davidson's death. "This tragedy is the result of a senseless act of violence that has no place in our city," he said in a statement Wednesday.

The Pasceri family issued a statement of condolence, adding that no words could reflect how "heartbroken we are by this tragedy."

The hospital conducted a drill in 2013 for an active-shooter situation. Betsy Nabel, the hospital's president, said she was "proud" of the staff response. She said there have been no discussions about installing metal detectors, which none of the city's hospitals have.

Contributing: Associated Press