Brigham and Women’s Hospital lowered its flag on Wednesday, one day after the shooting death of Dr. Michael Davidson. 
 
 Shortly after 11 a.m. Tuesday, a man walked into Brigham and Women’s Hospital, asked to speak with Dr. Michael J. Davidson, and, when the cardiovascular surgeon stepped into an exam room to speak, fired two shots. 
 
 Twelve hours later, police and hospital administrators announced that Davidson, a father of three whose wife is a plastic surgeon, had died after he was rushed to the emergency room and underwent surgery. 
 
 A preliminary investigation suggested his assailant, identified as Stephen Pasceri, 55, of Millbury, “had some issue” with prior medical treatment of his mother at the hospital, said Superintendent Robert Merner, head of the Bureau of Investigative Services. Marguerite E. Pasceri died Nov. 15. 
 
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 “There was a particular reason he targeted this doctor,” Police Commissioner William B. Evans said. 
 
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 Loud voices boomed from inside the exam room before the gun went off. A law enforcement official briefed on the incident said Pasceri fired two shots from a .40-caliber pistol, striking the doctor. Police found a gun near Pasceri’s body that they believe he used in the shooting. 
 
 A loudspeaker warned patients and staff of an emergency. Police conducting a room-to-room search soon found the shooter in the exam room, dead from an apparently self-inflicted gunshot. 
 
 “Dr. Davidson was a wonderful and inspiring bright light and an outstanding cardiac surgeon who devoted his career to saving lives and improving the quality of life of every patient he cared for,” Dr. Elizabeth Nabel, the hospital’s president, wrote in a late-night letter to staff members. “It is truly devastating that his own life was taken in this horrible manner.” 
 
 Davidson, 44, of Wellesley, has been a cardiovascular surgeon at the Brigham since 2006, and an assistant professor at Harvard Medical School. He graduated from Yale University School of Medicine in 1996 and did postgraduate training at Duke University Medical Center and the Brigham. 
 
 LinkedIn (left); Telegram & Gazette A preliminary investigation suggested Dr. Michael Davidson’s assailant, Stephen Pasceri (right), “had some issue” with prior medical treatment of his mother. 
 
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 In her letter to the Brigham staff, Nabel described the doctor’s passion for running — he celebrated his 40th birthday by tackling the Boston Marathon — and for medicine. He was part of a team that performed a landmark heart-valve procedure and helped establish what Nabel described as one of the most advanced operating rooms in the nation. 
 
 A 2001 edition of a Duke alumni magazine, under the headline “The Perfect Match,” shows a photo of Davidson kissing his future wife, Terri Halperin. 
 
 George Corbett, 61, a neighbor of Davidson’s, described him as “a very friendly man. When he [is] walking in the neighborhood, he would always say hello and he was always walking with one of his kids.” 
 
 Pasceri, the shooter, lived in a two-story Colonial-style house in Millbury with his wife, Teresa. He worked for a Milford company, the Waters Corp., which makes specialized laboratory equipment, according to company spokesman Jeff Tarmy, who did not know how long Pasceri worked there. 
 
 Millbury police Lieutenant Donald Desorcy said Pasceri was properly licensed to possess a firearm. “They are a very good family,” Desorcy said. “Never any problems, as far as we are concerned.” 
 
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 David Cofske, a neighbor, said the Pasceris raised four children next door and described Stephen Pasceri as “a calm, pleasant type of guy” who went camping with his family. 
 
 “It’s just such a shock,” Cofske said. 
 
 One neighbor said Pasceri was known in the neighborhood as “the church guy,” because he would regularly knock on doors to raise money for the Millbury Federated Church. 
 
 The Pasceri family issued a statement Tuesday night that said “our hearts go out to Dr. Davidson, his family, and friends. We are praying for them. . . . No words can truly express how heartbroken we are by this tragedy.” 
 
 When the shooting was reported at 11:04 a.m., a police officer on paid detail at the hospital was quickly joined by other officers and the hospital’s security force on the second floor of the Carl J. and Ruth Shapiro Cardiovascular Center, located across Francis Street from the hospital’s main entrance. 
 
 Witnesses said patients, staff, and visitors were trapped inside the building for about 45 minutes, some barricaded in exam rooms. Surrounding roads were cordoned off, and the MBTA briefly canceled service to the area. 
 
 “I want to thank the Boston Police Department for doing an extraordinary job of responding rapidly, being on the site, and taking control of the site in a very rapid manner,” said Nabel, the hospital president, adding, “I am extremely proud of the way our staff responded.” 
 
 Dina Rudick/Globe Staff Pasceri’s house in Millbury. 
 
 Meagan P. Mceachron, of Saratoga, N.Y., was on the second floor of the Shapiro Building, where her boyfriend underwent cardiac surgery Tuesday. About two minutes after she learned the surgery was done, she said, a loudspeaker announcement ordered the evacuation of the second floor. About the same time, she said, police officers rushed into the room, guns drawn, shouting at people to “Get down!” or “Get back!” 
 
 People started screaming and running, panic stricken, to the glass-enclosed walkway that connects the Shapiro to other hospital buildings, she said. 
 
 Irene Stefanidis was at the Shapiro with her father, whom she had brought there for testing. While they were inside a first-floor exam room, the loudspeaker crackled with the news that a life-threatening emergency was taking place on the second floor, and that everyone should go into a room and lock the door. Father and daughter huddled in the exam room for about 45 minutes until a second announcement told them to unlock the door and leave. 
 
 The Brigham does not have metal detectors at its entrances, according to spokeswoman Erin McDonough, who added that she believed no hospital in Boston has them. 
 
 Hospital shootings are so rare that they are sometimes compared to lightning strikes. A 2012 study of news reports by the Johns Hopkins Office of Critical Event Preparedness and Response identified 154 shootings from 2000 through 2011, with 235 injured or dead. The most common victim was the shooter, 45 percent, and physicians and nurses were rarely victims, the study found. 
 
 But because these incidents are so serious, hospitals in Boston have prepared for them. The Conference of Boston Teaching Hospitals produced a training video filmed at Boston Medical Center; all its members have response plans in place, said John Erwin, executive director. The video depicts a fictional scenario in which a man enraged by his mother’s death during an operation barges into the hospital with a gun. 
 
 Dr. Ron M. Walls, the Brigham’s executive vice president and chief operating officer, said the Brigham was one of the first hospitals in the country to train staff on how to respond to an “active shooter” situation, working with the Boston police. 
 
 The result, Evans said, was “a great response.” 
 
 The Brigham also worked with Boston police to make its own training video. The video instructs staff to assess whether it makes most sense to run, hide (barricading doors with hospital beds), or fight (disabling the attacker with a chair or fire extinguisher). 
 
 It ends with the words “Be aware and be prepared,” superimposed on a photo of the Shapiro Center. 
 
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 , and Kay Lazar of the Globe staff and Globe correspondent Zolan Kanno-Youngs contributed to this report. Felice J. Freyer can be reached at felice.freyer@globe.com ||||| They were putting on the loud speaker there was a life threatening emergency on the second floor," said witness Devin Cruz, who was inside at the time. 
 
 "For someone to walk into a hospital where healing is being done, people's lives are being saved...and take a life..or try to take a life...that's scary," witness James Pitelli said. 
 
 BOSTON ( MyFoxBoston.com ) -- The doctor who was shot Tuesday morning at Brigham and Women's Hospital died Tuesday evening after succumbing to his injuries.Dr. Michael J. Davidson, 44 of Wellesley, was the director of endovascular cardiac surgery, and an assistant professor at Harvard Medical School. Davidson leaves behind a wife and three children.Davidson was shot twice Tuesday morning, and was in surgery Tuesday evening, but later died as a result of the gunshot wounds he suffered.Brigham and Women's Hospital released a statement about Davidson's death."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 statement read in part. "It is truly devastating that his own life was taken in this horrible manner. At this time, Dr. Davidson's family has requested privacy, and we ask for your support in honoring their request during this very difficult time."Mayor Marty Walsh released a statement early Wednesday morning, calling the tragedy a "senseless act of violence" that has no place in Boston. "My thoughts and prayers are with his family and his colleagues at Brigham and Women's Hospital during this difficult time," Mayor Walsh's statement read.Boston police identified the shooter as 55-year-old Stephen Pasceri of Millbury.Millbury Police Lt. Donald Desorcy helped the Boston Police Department notify Pasceri's family."They say they were shocked, nothing they anticipated," Desorcy said. "We've had no issues at all with the family themselves." Pasceri was a husband, a father, and very involved in both his community and church.In a press conference, the Boston Police Department said Pasceri was found dead in an examination room with a self-inflicted gunshot wound. Three shots had been fired altogether.The incident happened just after 11 a.m. in the Shapiro Cardiovascular Center.The hospital was briefly placed on lockdown. Police came and ordered people out of the building."All of a sudden they had their guns drawn and they were saying hurry, hit the floor, down, stay down, stay low," witness Kathy Pitelli said."[The shooter] came into the hospital asking for this particular doctor," Boston Police Commissioner William Evans said. "We don't know why. That's something we're looking into."Pasceri reportedly fired two shots at Davidson and then turned the gun on himself.Multiple sources told FOX 25 that Pasceri's mother recently died, and Davidson had treated her.
– The Brigham and Women's Hospital cardiovascular surgeon shot twice yesterday by a lone gunman who police believe was upset by his mother's death has succumbed to his injuries, reports the Boston Globe. Dr. Michael Davidson died late yesterday, roughly 12 hours after police say 55-year-old Stephen Pasceri walked into the Boston hospital, asked to see Davidson, and shot the 44-year-old in an exam room. Pasceri, who was found dead of a gunshot wound believed to be self-inflicted, "had some issue" with the treatment of his mother, says the head of the Bureau of Investigative Services. Pasceri's mom, Marguerite Pasceri, died in mid-November. "There was a particular reason he targeted this doctor," says Boston's police commissioner. Pasceri owned the weapon legally, and the dad of four was mostly known in his Millbury neighborhood for raising money for his church. "They are a very good family," says a Millbury cop, who tells WFXT that "they were shocked, [this was] nothing they anticipated." His family issued a statement last night, saying, "Our hearts go out to Dr. Davidson, his family, and friends. We are praying for them. ... No words can truly express how heartbroken we are by this tragedy." Davidson is survived by his three kids and wife, who is a plastic surgeon. He was hailed as "a wonderful and inspiring bright light and an outstanding cardiac surgeon" by the Brigham and Women's Hospital president last night. The hospital, like many, does not have metal detectors; the Globe notes that hospital shootings are rare enough to be compared to lightning strikes.