The doctor killed in a shooting rampage at a New York City hospital was working a colleague’s shift, the New York Post reported Saturday.

Tracy Sin-Yee Tam, 32, had been a doctor for two years.

She was at Bronx-Lebanon Hospital in the Bronx Friday working a shift for another doctor, the paper reported.

“She didn’t have to be there. She doesn’t work in the hospital, she works in the clinic,” a neighbor, 58-year-old Mahmudur Rahman told the paper.

Tam was killed in an afternoon bloodbath that left six others wounded.

Cops say the gunman Dr. Henry Bello went to the hospital with an assault rifle under a doctor’s white lab coat.

Bello ultimately turned the gun on himself before he could be captured.

The Post reported that Bello resigned from Bronx-Lebanon in 2015 amid a sexual harassment scandal and vowed to return and kill a coworker.

That coworker was a hospital resident who wasn’t working Friday, the paper reported.

HOSPITAL SHOOTING: DOCTOR KILLED, MULTIPLE PEOPLE INJURED, POLICE SAY

Meantime, only one of the six wounded victims, a doctor, remained in critical condition Saturday.

Three victims were upgraded from critical to stable condition, a fourth remained in stable condition and a fifth, who had been in stable condition, was transferred to another hospital for specialized surgery.

Bronx Lebanon vice president Errol C. Schneer said the fact that five victims were in stable condtion Saturday was testament to how "heroically" staff responded to the shooting.

"Many of our staff risked their own lives to save patients," Schneer told reporters.

The Daily News reported Saturday that it had received an email purportedly from Bello about two hours before the rampage.

"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 getting a chance to practice medicine.

His former co-workers described a man who was aggressive, loud and threatening. After he was forced to resign amid sexual harassment allegations, Bello told colleagues he would be back to kill them.

"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.

"We fired him because he was kind of crazy," Dr. Maureen Kwankam told the Daily News. "He promised to come back and kill us then."

The Associated Press contributed to this report.

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