A retired New York City police officer was sentenced on Thursday to 15 months in prison for running a multimillion-dollar online escort service that catered to wealthy clients who arranged assignations at their homes, at major hotels and in at least one instance on a five-day trip to a secluded resort in Jamaica.

At a brief hearing in Federal District Court in Brooklyn, the former officer, Michael Rizzi, took responsibility for managing the service, BJM/Manhattan Stakes and Entertainment, which advertised on dozens of websites with names like Lush Playmates and Elite Club NYC.

“There’s no one else to blame but me,” Mr. Rizzi told Judge Carol B. Amon moments before she sentenced him. “It was the stupidest thing I’ve ever done in my life.”

Mr. Rizzi pleaded guilty in October to one count of money-laundering conspiracy.

According to federal prosecutors, the inquiry into the escort operation began in 2012 when the police and agents from the Internal Revenue Service and the Department of Homeland Security began to investigate a Staten Island man named Marc J. Schulman, who ran an online sex business called Pure Platinum Models. Prosecutors claim that financial records linked shell companies that Mr. Schulman used to Mr. Rizzi’s business, BJM. Mr. Rizzi eventually took over Pure Platinum Models, the prosecutors said, renaming it and running it from his home in Bensonhurst, after Mr. Schulman pleaded guilty to money laundering charges in 2015.