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A housing development in a small upstate New York town where members of the cultlike group Nxivm had homes functioned as the set of a “horror movie,” and the group’s leader, Keith Raniere, played the role of the central villain, a federal prosecutor told jurors on Monday.

During closing arguments in Mr. Raniere’s racketeering and sex trafficking trial, the prosecutor, Moira Penza, pointed to a map of a Clifton Park neighborhood where many Nxivm members lived, then described what witnesses said had happened inside several homes.

In one, she said, a naked woman was held down — “her arms above her head like a sacrifice, screaming” — while she was branded with Mr. Raniere’s initials. In another, a terrified woman named Nicole was tied to a wooden table, blindfolded, while someone performed oral sex on her, Ms. Penza said.

A third held an archive of sexually explicit photographs taken by Mr. Raniere, who was known as Vanguard, she said. They showed multiple women within Nxivm, including one Ms. Penza called “his trophy, his sexual conquest” — a 15-year-old girl from Mexico.