A New York man will spend 18 years in prison for pimping a vulnerable minor for sex around Boston.

U.S. District Court Judge Nathaniel M. Gorton sentenced Sherriff Cooper, 37, to 18 years in prison to be followed by five years of supervised release and ordered him to pay $97,200 in restitution to the victim. Cooper is incarcerated at the Donald W. Wyatt Detention Facility in Rhode Island.

A federal grand jury convicted Cooper on Feb. 29 on charges of sex trafficking of a minor by force, fraud and coercion; transportation of a minor with intent to engage in criminal sexual activity; and forced labor. He began pimping his victim in 2018 and was charged and arrested by the FBI in 2021.

Court records show that Cooper submitted repeated motions to have his conviction overturned and, in June, filed a civil suit against his victim demanding $11 million “for the irreparable harm suffered by the defendant retaliation of the plaintiffs protected speech and for falsely accusing the plaintiff of crimes he did not commit.”

Cooper, who was 31 at the time, met his then-15-year-old victim in 2017 while working as a security guard at a residential program for pregnant teens. The victim, prosecutors say, had run away from a Massachusetts Department of Children and Families center for young mothers in Dorchester.

Cooper at first began a sexual relationship with the girl and the pair moved into the minor’s mother’s apartment together where he started beating and drugging her. DCF placed her in a new program in Newburyport, and Cooper would come by, prosecutors say in a sentencing memo, to have sex with her in the parking lot “and abusing her when he thought she was ‘cheating’ on him with boys her own age.”

“In February 2018, Minor A ran away from the program and began living with Cooper,” prosecutor Stephen Hassink wrote in the sentencing memo. “She had no family to take her in and nowhere else to go. She had no money, no job, and no support. Cooper was waiting.”

That year, Cooper started pimping her out around Boston. He pocketed all the money and, prosecutors wrote in court documents, “used violence, threats of violence and coercion to make the victim engage in commercial sex for his financial benefit.”

But that wasn’t all. He had a fake ID made for her and transported her down to his home state of New York where he got her employed at a strip club and again pocketed all of the money. And, according to an affidavit Cooper filed himself in the case, he and his victim now share a son.

Acting U.S. Attorney Joshua Levy said Cooper “viciously and cruelly exploited a vulnerable minor.”

“When he lost his job, Mr. Cooper decided he would rather sex traffic a vulnerable child for financial gain than seek legitimate employment — all the while physically abusing and threatening her,” Levy said in a statement.

“Her bravery and courage in holding this defendant accountable is truly remarkable. Mr. Cooper’s refusal to accept any responsibility for his crimes or show remorse for the lifelong harm he inflicted underscores why he is truly deserving of this significant sentence.”