Police have brought down a drug den operating out of a one-family home across the street from the 92nd Street Y, authorities said.

They arrested more than 10 people earlier this month and confiscated crack cocaine, between 30 and 40 hypodermic needles, and spoons and pipes with crack cocaine residue from the brownstone at 1380 Lexington Ave., on the northwest corner of 91st Street, law enforcement officials said. The drug business was running 24 hours a day, 7 days a week, officials said, and worked like a “shooting gallery,” with buyers remaining in the house to use drugs.

The 92nd Street Y is one of Manhattan’s most popular venues for courses, lectures, concerts, and sports, and it operates a nursery school that may be New York’s most desirable.

The investigation of alleged narcotics activity at the Upper East Side townhouse began in March, officials said. Although police focused on the sale and use of crack cocaine, police officials said they suspect heroin was being used there as well.

On two occasions since June, Kenny Cobb, 34, allegedly sold crack cocaine to undercover police operatives inside the Lexington Avenue house, according to the criminal complaint. On August 9 at 6:45 a.m., Mr. Cobb “possessed numerous hypodermic needles, spoons with crack/cocaine residue, pipes with crack/cocaine residue and a quantity of crack/cocaine,” the court document alleges. On August 12, he pleaded guilty to criminal possession of a controlled substance and was sentenced to 30 days in jail.

A resident of the house, Judy Zaruchi (called Judith Zarucki by police officials), 43, allegedly oversaw the illicit activity. She and three others were also arrested August 9 and charged with criminal possession of a controlled substance, criminal possession of a hypodermic instrument, and criminal use of drug paraphernalia, the complaint says.

A 30-year-old man described as Ms. Zaruchi’s live-in boyfriend, Boris Goldenberg, 30, was apprehended the following day at 90th Street and Third Avenue and was charged by the district attorney’s office with a past assault. According to police officials, Mr. Goldberg was wanted for the nonfatal stabbing of a 21-year-old man, who had also resided in the house, during the course of a dispute earlier in the year inside the brownstone. In addition, Mr. Goldberg was wanted for an incident of domestic violence involving his girlfriend, officials said.

Police also arrested other people who were inside the home on the morning of August 9, officials said, but their cases were later dismissed by the district attorney’s office.

Ms. Zaruchi was allegedly running the place as though it were a hotel. The New York Fire Department issued a vacate order and violations on August 14, Fire Department officials said, because the brownstone was allegedly divided into five or six makeshift lodgings.

There have been other problems at the landmark-designated building, authorities said, including two nonfatal overdoses possibly due to heroin. It could not be determined last night who owns the brick, four-story townhouse.