A townhouse on the Upper East Side that up until recently was an alleged crack cocaine den appears to be undergoing a renaissance.

The one-time drug den, which is across the street from the 92nd Street Y on Lexington Avenue and a few blocks away from the Guggenheim Museum, is being gutted and renovated now, according to a man who identified himself as the contractor.

The townhouse, once the home of the film director Sidney Lumet, was the scene of a large police drug raid in 2005 and, according to several neighbors, remained a haven for drug users up until recently.

“It’s really calmed down in the last six months,” a fashion designer who works across the street from the townhouse, Shawn Korman, said.

About four months ago the property was purchased for $4.1 million by Thomas Wexler, who is the director of townhouses for Corcoran Group Inc. Corcoran brokered the sale and Mr. Wexler was the listing agent.

It was quite a deal for Mr. Wexler, considering that similarly sized townhouses in Carnegie Hill sell for millions more. In the past year, properties of similar square footage in the neighborhood have sold for between $5.75 million and $12.8 million, according to a property research Web site, PropertyShark.com.

Mr. Wexler took out a mortgage of $4.89 million with Wells Fargo Bank N/A, according to PropertyShark.com. The $890,000 more than the purchase price is likely funding the renovations.

Mr. Wexler was reached at his office, but did not want to comment for this article.

Mr. Wexler bought the property from Rose 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. Ms. Zarucki took a loss on the sale of the home, which she bought for $5.2 million in 2002, according to city records.

Ms. Zarucki was reached on the telephone at her home on the Upper East Side, but declined to comment for this article.

The townhouse’s transformation began several months before Mr. Wexler bought the home, according to several neighbors.

The neighbors, who asked not to be identified, said Ms. Zarucki’s daughter, Judith Zarucki, moved out of the townhouse at that time.

Judith Zarucki was identified in a court complaint as the alleged main tenant of the townhouse after a drug raid in 2005, where more than 10 people were arrested and police confiscated crack cocaine, hypodermic needles, and other drug paraphernalia.

Court records do not indicate that Ms. Zarucki was indicted in the incident.

Mr. Korman and another neighbor said that there had been at least two drug overdoses at the home in the past three years and a shooting a block away. Mr. Korman also said he witnessed two men attempting to break into the apartment last year.

But with an industrial-size dumpster lining the sidewalk, laborers milling around the property, and a renovation permit issued on May 2 by the New York City Department of Buildings, it appears the townhouse will soon be fully restored.

“I feel a lot safer now,” a neighbor who has lived on the block for more than 20 years said.