A woman is escorted by officers near the Bronx Lebanon Hospital in New York after a gunman opened fire there on Friday, June 30, 2017. The gunman, identified as Dr. Henry Bello who used to work at the... (Associated Press) 
 
 NEW YORK (AP) — A doctor who appears to have been the target of a former physician who started shooting at a hospital, killing one person and injuring six, said he has no idea why he would have been singled out. 
 
 Dr. Kamran Ahmed told the New York Post he wasn't the only one Dr. Henry Bello had a problem with. 
 
 However, "he never argued with me," Ahmed said. "I don't know why he put my name." 
 
 A law enforcement official told The Associated Press that Bello arrived at Bronx Lebanon Hospital in the Bronx on Friday with an assault rifle, which was bought in upstate New York about a week earlier, hidden under his lab coat and asked for a doctor he blamed for his having to resign, but the doctor wasn't there at the time. The law enforcement official wasn't authorized to discuss an ongoing investigation and spoke on the condition of anonymity. 
 
 Ahmed, who specializes in the early detection and treatment of dementia, said Bello "had a problem with almost everybody, so I'm not the only one. That's why they fired him, because so many people complained." 
 
 Authorities said Bello went to the 16th and 17th floors and started shooting anyway, killing Dr. Tracy Sin-Yee Tam, who, like him, was a family medicine doctor. Hospital officials said that Tam normally worked in one of the hospital's satellite clinics and was covering a shift in the main hospital as a favor to someone else. 
 
 "It makes you think that anything can happen to anybody," said Tam's neighbor Alena Khaim, who saw Tam's sister outside the home Friday night overcome with grief, shaking and unable to walk. "She was such a sweet girl. You would never think something like that would happen, but it happened." 
 
 Before the shooting, Bello sent an email to the Daily News, blaming colleagues he said forced him to resign two years earlier. 
 
 "This hospital terminated my road to a licensure to practice medicine," the email said. "First, I was told it was because I always kept to myself. Then it was because of an altercation with a nurse." 
 
 Bello's former co-workers described a man who was aggressive, loud and threatening. Bello had warned his former colleagues when he was forced out in 2015 that he would return someday to kill them. 
 
 "All the time he was a problem," said Dr. David Lazala, who trained Bello. 
 
 When Bello was forced out in 2015, he sent Lazala an email blaming him for the dismissal. 
 
 Bello died from a self-inflicted gunshot. The six injured people were hospitalized. 
 
 Detectives searched the Bronx home where Bello was most recently living and found the box where the gun came from. They later determined it was bought at a gun shop in Schenectady on June 20. 
 
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 This story has been corrected to show Bello had an assault rifle, not an automatic weapon. ||||| A woman is escorted by officers near the Bronx Lebanon Hospital in New York after a gunman opened fire there on Friday, June 30, 2017. The gunman, identified as Dr. Henry Bello who used to work at the... (Associated Press) 
 
 NEW YORK (AP) — A doctor angry that his career was derailed at a New York City hospital toted an assault rifle past security in search of a colleague he was going to hold responsible. When that person wasn't there, he opened fire anyway, killing a doctor who was only there covering a shift as a favor, authorities said Saturday. 
 
 The new details of Dr. Henry Bello's rampage emerged along with an email rant against colleagues he blamed for forcing him to resign from Bronx Lebanon Hospital amid sexual harassment allegations two years earlier. The email was sent to the New York Daily News just two hours before the shooting Friday afternoon that left six other people wounded and Bello dead from a self-inflicted shot. 
 
 "This hospital terminated my road to a licensure to practice medicine," the email said. "First, I was told it was because I always kept to myself. Then it was because of an altercation with a nurse." 
 
 He also blamed a doctor for blocking his chances at practicing medicine. 
 
 Bello had warned his former colleagues when he was forced out in 2015 that he would return someday to kill them. 
 
 A law enforcement official told The Associated Press that Bello arrived at the hospital with the assault rifle hidden under his lab coat and asked for a specific doctor whom he blamed for his having to resign, but the physician wasn't there at the time. The official spoke on anonymity because the person was not authorized to discuss an ongoing investigation. 
 
 It was not clear if Bello knew Dr. Tracy Sin-Yee Tam, 32, who was killed in the shooting on the 16th and 17th floors of the hospital and was, like him, a family medicine doctor. Hospital officials said that Tam normally worked in one of the hospital's satellite clinics and was covering a shift in the main hospital as a favor to someone else. 
 
 "It makes you think that anything can happen to anybody," said Tam's neighbor, Alena Khaim, 23, who saw Tam's sister outside the home Friday night overcome with grief, shaking and unable to walk. "She was such a sweet girl. You would never think something like that would happen but it happened." 
 
 Judy Beckles-Ross, 46, said she's not surprised Tam volunteered to cover the shift. 
 
 "She never said no," said Beckles-Ross, a friend from medical school who knew her for 11 years. "She had a good heart. Anybody that needed help, she would help them." 
 
 The six others who were injured — a patient, two medical students and three physicians — largely suffered gunshot wounds to the head, chest and abdomen. One physician remained in critical condition and the rest were stable, officials said Saturday. 
 
 Hospital vice president Errol C. Schneer said his staff responded heroically. 
 
 "Many of our staff risked their own lives to save patients," Schneer told reporters at the hospital where the 16th and 17th floors remained closed, and staffers were still recovering from the rampage that sent people diving for cover and huddling in patients' rooms while the gunman was on the loose. Adding to the chaos, authorities said, was a fire alarm that went off when Bello attempted to set himself ablaze, the flames extinguished by sprinklers, shortly before he shot himself. 
 
 Detectives searched the Bronx home where Bello was most recently living and found the box where the gun came from. Investigators were checking serial numbers and trying to determine where it was purchased. 
 
 His former co-workers described a man who was aggressive, loud and threatening. 
 
 "All the time he was a problem," said Dr. David Lazala, who trained Bello as a family medicine doctor. When Bello was forced out in 2015, he sent Lazala an email blaming him for the dismissal. 
 
 Dr. Maureen Kwankam told the New York Daily News that "he promised to come back and kill us then." 
 
 According to New York State Education Department records, Bello graduated from Ross University and had a permit to practice as an international medical graduate that was issued on July 1, 2014, and expired last year on the same day. 
 
 In 2004, the doctor pleaded guilty to unlawful imprisonment, a misdemeanor, after a 23-year-old woman told police Bello grabbed her. He was arrested again in 2009 on a charge of unlawful surveillance, after two different women reported he was trying to look up their skirts with a mirror. That case was eventually sealed. 
 
 Schneer told the New York Times that the hospital did not know about Bello's criminal history when he was hired. 
 
 "At that time, and as a result of a human resources and security department background check, which includes fingerprinting, there was no record of any conviction for sexual abuse," he said. 
 
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 Associated Press writers Larry Neumeister, Rebecca Gibian, Steve Peoples and Karen Matthews contributed to this report.
– A doctor who appears to have been the target of a former physician who started shooting at a hospital, killing one person and injuring six, says he has no idea why he would have been singled out. Dr. Kamran Ahmed tells the New York Post he wasn't the only one Dr. Henry Bello had a problem with. However, "he never argued with me," Ahmed says. "I don't know why he put my name." A law enforcement official tells the AP that Bello arrived at Bronx-Lebanon Hospital Center in the Bronx on Friday with an assault rifle, which was bought in upstate New York about a week earlier, hidden under his lab coat and asked for a doctor he blamed for his having to resign (presumably Ahmed), but the doctor wasn't there at the time. Authorities say Bello went to the 16th and 17th floors and started shooting anyway, killing Dr. Tracy Sin-Yee Tam, who, like him, was a family medicine doctor. Hospital officials say that Tam normally worked in one of the hospital's satellite clinics and was covering a shift in the main hospital as a favor to someone else. Before the shooting, Bello sent an email to the Daily News, blaming colleagues he said forced him to resign two years earlier. "This hospital terminated my road to a licensure to practice medicine," the email said. Bello's former co-workers described a man who was aggressive, loud, and threatening. Bello had warned his former colleagues when he was forced out in 2015 that he would return someday to kill them. Ahmed says Bello "had a problem with almost everybody" and "that's why they fired him, because so many people complained." Bello died from a self-inflicted gunshot. The six injured people were hospitalized.