Two weeks after a police raid at a $7 million townhouse on the Upper East Side that the authorities allege was used as a crack den, neighbors and local building workers complained yesterday that frequent late-night visits by strangers have resumed.

On August 9, police stormed 1380 Lexington Ave. – across the street from the 92nd Street Y in one of Manhattan’s most affluent neighborhoods – and arrested more than 10 people. The authorities said crack cocaine, hypodermic needles, and other drug paraphernalia were confiscated.

The alleged main tenant of the drug den, Judith Zarucki, 43, was arrested and charged with several felonies, including possession of a controlled substance. Neighbors and building workers said Ms. Zarucki has returned to the neighborhood.

A man who answered the front door at 1380 Lexington Ave. said he would not comment to the press.

In 2002, the townhouse, which was once the property of the famed film director Sidney Lumet, was sold to Rose Zarucki for $5.2 million. Ms. Zarucki, who along with her deceased husband, Charles, was a Holocaust survivor and was listed in 2000 as donating more than $100,000 to the Museum of Jewish Heritage. Now 75, she maintains residences on the Upper East Side and in Aventura, Fla. She did not answer phone messages from The New York Sun.

Judith Zarucki has been a resident of the Upper East Side in several different apartments at least since the mid-1980s. According to neighbors, Rose Zarucki gave use of the townhouse to her adopted daughter, Judith, and grandchildren. Neighbors said the children were no longer living with their mother.

Police alleged Ms. Zarucki was running an illegal boarding house, and the Fire Department issued a vacate order on August 14, saying the residence had been improperly divided into five or six makeshift lodging units. Other problems reported at the address have included two non-fatal drug overdoses, possibly from heroin.

Charges against the other people arrested in the raid two weeks ago have been dropped, but another reported resident of the townhouse, Boris Goldenberg, 30, who has been described as Ms. Zarucki’s boyfriend, was arrested the next day in connection on other charges. He remains in custody.

His mother, Valentina Goldenberg, said in a telephone interview yesterday that the family emigrated from Ukraine in 1976. She said she has not been in touch with her son.

Several neighbors and local building workers, who all declined to be quoted by name, described the slow decline of the building at 1380 Lexington in the past two years.

One neighbor said visitors go in and out of the townhouse throughout the day and night. Speaking of Judith Zarucki, the neighbor said: “She said she would take in troubled kids and put them on the right path – that was her story.”

A doorman, who requested anonymity, said every night after 11 o’clock a group of young men and women gather outside the townhouse on the corner of 91st Street and Lexington. The doorman said he warned his daughter, who frequents the Y, not to walk down 91st Street.

“It’s dangerous, and the police aren’t doing anything,”he said. “It’s still going on. Always at night there is a lot of action there.”

Another local building worker said Ms. Zarucki and her guests – who include several young women – sleep all day and emerge in the evening.

The proprietor of a local newsstand said he used to see a crowd outside the townhouse when he arrived at work at 7 a.m. The owner of a local bookbinding store, Herb Weitz, described a heavily armed police raid on the house on August 9, visible from his store on Lexington Avenue.

“I thought it was a bomb,” he said.

Yesterday, all the windows of the townhouse were shuttered and taped with newspaper. The building, listed in city real estate records as a single-family residence, contains more than 4,000 square feet. Its south-facing brownstone facade is punctuated with stained-glass windows and covered with wisteria – a neighborhood landmark said to attract visitors each spring.

A city assessment of the building placed its current value at $6.9 million.

For many years, ending in 1992, the 1899 townhouse belonged to Mr. Lumet, whose many credits include “Network” and “Dog Day Afternoon.” It sits across the street from the 92nd Street Y, a popular destination for cultural and social events and recreation, and home of a celebrated nursery school, and down the street from a daycare center and the independent Brick Church School.