We've known that Westchester enclave Bedford Hills was pretty ritzy, but we had no idea that one of its appeals was an S&M "dungeon" run out the basement at a $3 million estate! Not only that, the dungeon master, "Mistress" Sandra Chemero was renting the place from an "ultra-Orthodox" yeshiva. Oy vey! Naturally, the school served her with eviction papers.

The police arrested Chemero on Tuesday for prostitution and weapons possession (a stun gun, not the "paddles, whips and bondage racks" found). Chemero was a dominatrix, but allegedly offered to have sex with an undercover cop. The police are also investigating her business records, and the Post details what Chemero was advertising via her now inacessible website, The Sovereign Estate.

"The Sovereign Estate is a female-led household, headed by an elegant, attractive dominant woman," she advertised.

"Situated on four private acres, in a century-old stately manor, here life is devoted to female superiority, proper training and etiquette for the betterment of men.

"There is something unique about serving your Mistress in a home designed and appointed especially for her enjoyment. The Estate offers a myriad of opportunities found nowhere else," it adds.

Chemero, who is out on bail, had been renting the estate for $3,000/month. Luxist happened to feature a $12 million Bedford Hills estate (via The Real Estate); other celebrities in the area include Martha Stewart, Glenn Close, and Ralph Lauren. And the police were tipped off by an anonymous letter. We bet it was an unhappy client.