NEW YORK (CBSNewYork) — As we learn more about the gunman, hospital workers are remembering the doctor killed in a shooting at Bronx-Lebanon Hospital Friday.

32-year-old Dr. Tracy Tam, of Jamaica, Queens, was shot and killed Friday afternoon when police say Dr. Henry Bello went on a revenge-driven rampage.

Bello sneaked an AM-15 assault rifle under a white lab coat to the 16th floor and shot 7 people before fatally shooting himself, according to police.

Doctor Killed In Bronx-Lebanon Hospital Center Shooting Identified As Jamaica, Queens Woman

“We certainly are grieved throughout the hospital by her passing,” Bronx-Lebanon spokesperson Errol Schneer told CBS2. “It’s a very tragic event for us as well.”

Officials say Bello resigned in 2015 amid sexual harassment allegations.

Gunman Opens Fire At Bronx-Lebanon Hospital Center: 1 Victim Dead, 6 Wounded

Sources say he was looking for a specific doctor Friday who wasn’t at the the hospital. Instead, he fired at another, yelling out, “why didn’t you help me when I was getting in trouble?”

The intended target later told police Bello was always belligerent and would get into verbal arguments with nurses and staffers, sources say.

Some coworkers remember Bello threatening to kill people after he left two years ago, while the hospital claims it was never notified.

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“We’re not aware of such reports,” Schneer said in a Saturday press conference.

Meanwhile, the New York Daily News reported Bello sent them a letter hours before the deadly shooting, saying in part ‘The hospital terminated my road to a licensure to practice medicine,” and, “it remains to be seen if my life is meaningless or disposable.”

PHOTOS: Shooting At Bronx-Lebanon Hospital Center

Officials say all but one of the victims were hospital employees. Dr. Tam had graduated from residency exactly one year before her death.

“It was very unfortunate that you know, that the tragedy happened to her because she was such a nice person,” coworker Marc Duplessy told CBS2.

One of Tam’s coworkers has set up a GoFundMe account for her family.

Sources tell CBS2 that Bello had been arrested several times, including a 2004 arrest for sexual abuse.

Of the six victims still recovering, one remains in critical condition according to hospital officials.

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