Accused Nxivm sex cult leader Keith Raniere was “a crime boss” who operated out of an upstate neighborhood that was so unassuming, it was creepy, a Brooklyn prosecutor said in closing statements Monday.

“Yes, it looks like the American dream,’’ Assistant US Attorney Moira Penza said of the housing development that included homes where Raniere and some of his top female lieutenants allegedly branded slaves and forced them into sex acts.

“But if we’ve learned anything from this trial, it’s that looks can be deceiving,’’ she said.

“The closed doors of these cookie-cutter homes could be right out of a horror movie. A look behind these doors reveals the inner workings of this criminal enterprise.”

Penza added that the alleged sex trafficker may have been known as a “human leader, a mentor, a guru’’ to his brainwashed followers, but jurors “saw him for what he really was: a con man, a predator, a crime boss.

“You heard the defendant in his own voice directing his crimes,” the prosecutor said of Raniere.

“Keith Raniere was at the center of this enterprise, he was the boss.’’

Penza told jurors that the group’s secret master-slave society, DOS, was never meant to empower women — but just a way to supply himself with a never-ending supply of women.

“The defendant did not create DOS to be a sisterhood,” she said. “To know why the defendant created DOS, look at his own words.”

Messages projected in court then showed a 2015 chat between Raniere and his first alleged sex slave, Camila.

“I think it would be good for you to own a f–k toy slave for me that you could groom and use as a tool to pleasure me,” he wrote in October 2015 to the woman, who prosecutors claim he started having sex with when she was 15.

“All of this was for him, to satisfy the defendant’s desire for sex, for power, for control,” the prosecutor said.

Raniere is facing trial for sex-trafficking and other charges. If convicted, he faces life behind bars.