Henry Bello, the gunman who wounded six people and killed a doctor at Bronx-Lebanon Hospital on Friday, was a former house physician at the hospital who'd spent much of the past few years living in homeless and transitional centers in Manhattan. He also had a history of sexual harassment, and was forced to resign from his job in 2015 after alleged sexual harassment of a co-worker.

The 45-year-old Bello's troubled past, and his mental state leading up to the shooting spree, have started to come into focus in the days after Friday's rampage. In a longer feature published Saturday night, the Times traces the doctor's "slow journey to the medical profession, which was punctuated by bankruptcy, at least two arrests and recent sojourns in homeless shelters." According to former neighbors and hospital workers who spoke with the newspaper, Bello's last known address was a homeless shelter near Bellevue Hospital on 30th Street, and he'd previously lived at the Bowery Missions Men's Center on the Lower East Side—a transitional housing facility for those struggling with drug addiction.

Several Lower East Side residents recalled seeing Bello near the Bowery Mission in recent weeks, though it's unclear if he was enrolled in a treatment program. Records show that he was living in the 77-bed center in 2014, the same year he was hired by Bronx-Lebanon. "He was very to himself, very quiet, looking down," one neighbor told the Times. "I never saw him with other people."

In 2004, Bello was busted on charges of sexual abuse and unlawful imprisonment for allegedly grabbing a 23-year-old woman by the crotch and attempting to carry her away. The sexual abuse charge was ultimately dropped, and Bello was sentenced to community service for unlawful imprisonment. He'd also had past arrests for burglary, public urination, and turnstile jumping, according to police sources who spoke with NBC 4.

Asked how the doctor could have passed a criminal background check, Errol C. Schneer, a hospital spokesman, said Saturday that "there was no record of any conviction for sexual abuse."

Just hours before Friday's rampage, Bello emailed the Daily News to complain that Bronx-Lebanon Hospital had "terminated my road to a licensure to practice medicine" due to "bogus complaints" from a female doctor. In that three-paragraph letter—which offers no explicit warning of the coming violence—Bello wrote that he congratulated the doctor who got him fired, telling her "it remains to be seen if my life is meaningless or disposable."

Bello worked at the hospital from August 2014 to February 2015 and resigned before he could be fired, according to Schneer. Dr. Sridhar Chilimuri, the hospital's physician in chief, told CNN that the hospital had been unhappy with Bello's performance, and that he left under "unfortunate" circumstances.

According to law enforcement officials who spoke with the Daily News, Bello screamed "Why didn’t you help me out when I was getting in trouble?" as he opened fire on the 16th floor nurses station. He later died from a self-inflicted gunshot wound.

Tracey Tam, who Bello shot and killed, was a physician who was covering for the colleague that Bello was looking for, according to the Daily News. Dr. Kamran Ahmed told paper he was "shocked" to hear he was Bello's target, adding, "He had a problem with almost everybody."

Of the six wounded, three are doctors, two are medical students, and one is a Bronx-Lebanon patient, law enforcement officials said Saturday.