An 83-year-old transgender woman who spent decades in prison for two unrelated killings and is now charged in connection with the discovery of a woman's torso was allegedly captured on surveillance video riding on a motorized wheelchair sitting on the victim's severed leg while inside a store. 

Harvey Marcelin is charged with dismembering 68-year-old Susan Leyden, whose body – without her head, arms and legs – was found in a shopping cart by a passerby on March 3 in Brooklyn, the New York Police Department said. She is charged with second-degree murder, evidence tampering, and concealing a dead body.

"This is a gruesome and barbaric homicide which resulted in a headless torso being disposed of on a New York City corner," NYPD Chief of Detectives James Essig said during a news briefing. "And it takes a serial killer off our streets."

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Harvey Marcelin, 83, was caught in surveillance video sitting on a severed leg while riding on a motorized wheelchair, the New York Police Department said. (WNYW)

Authorities said Marcelin and Leyden, who had been living in an LGBTQ shelter for eight months, knew each other for at least two years but the nature of their relationship was unclear. 

On March 1, Marcelin and another woman went to a Home Depot store in Manhattan and purchased a saw, trash bags, and cleaning fluid, Essig said. The other woman has cooperated with detectives, he said. 

The next day, Marcelin was seen on surveillance footage leaving the shopping cart behind on the street, police said. It was discovered six hours later and a passerby notified the police, who discovered the dismembered body inside a trash bag.

During a search of Marcelin's apartment on March 4, detectives found a human head and other body parts, Essig said. On March 7, a human leg was found when Marcelin was seen in the wheelchair a few blocks from the murder scene, police said. 

New York Police Commssioner Keechant L. Sewell updates the news media on several cases investigators are working on.  (NYPD)

Video surveillance released by the NYPD showed Marcelin inside a store on the wheelchair with a leg on the seat, Essig said.

"The bottom from the leg, the leg from the knee down, she was sitting on," he said. 

He added that investigators were still trying to determine a motive for the killing "but based on her history, she's capable of a lot of evil things out there."

Marcelin previously served more than 50 years in prison for two other slayings. She was on lifetime parole for manslaughter, according to a New York State database. 

In 1957, she was convicted of felony assault and has a rape conviction from 1963, police said. On April 18, 1963, she allegedly shot and killed a woman in Harlem. She was convicted and served 20 years in prison and was released in 1984 on lifetime parole. 

NYPD Chief of Detectives James Essig. (WNYW)

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In November 1985, Marcelin stabbed a girlfriend to death in Central Park and placed the body in a trash bag and left it on the street, Fox affiliate WNYW-TV reported. She was convicted of first-degree manslaughter and was paroled again in August 2019.