The June 1998 death of Brigette Murray, a college student who overdosed after taking ecstasy at the club, prompted the undercover drug buys that led to the city's lawsuit, he said.

Going after all the members might involve existing warrants or undercover drug buys, the professor said.

He drew chuckles once when he donned a leather jacket, and, trailing camera crews, made a televised "undercover" drug buy.

Mr. Mattingly, above, shot Michael Newby, 19, three times in the back after an undercover drug deal went wrong.

Using this information, detectives made a series of undercover drug buys and arrested 31 people.

The police shot and seriously wounded a man early yesterday during an undercover drug buy on a Harlem street corner, firing 21 shots, police officials said.

In Manhattan, residents have staged undercover drug buys and made citizens' arrests of drug dealers.

Raul Lopez Alvarez, 28 years old, made the comments in Spanish to an undercover drug agent in a conversation at a Los Angeles hotel.

Elder brother Charlie Kray was released in 1975 after serving seven years, but returned to prison in 1997 for conspiracy to smuggle cocaine worth £69m in an undercover drugs sting.

What follows is a firsthand description of undercover drug buys in New York City, of surveillances and arrests.