A group of retired federal drug enforcement agents sued NBC Universal yesterday, saying the movie “American Gangster” falsely made them out to be villains in the story of a Harlem heroin trafficker played by Denzel Washington.

The suit, filed in federal court in Manhattan, claims that the movie defamed hundreds of DEA agents and New York police officers by claiming at the end that Frank Lucas’s collaboration with prosecutors “led to the convictions of three quarters of New York City’s Drug Enforcement Agency.”

Lucas became a government informant after his conviction in 1975, and his tips led to the prosecutions of several fellow drug dealers.

According to the lawsuit, no DEA agents or New York police officers were ever convicted as a result of tips provided by Lucas. “This is absolutely off-the-wall,” a prosecutor in the federal case against Lucas in 1975 who now represents the DEA agents, Dominic Amorosa, said.

Mr. Amorosa said the filmmakers had unfairly blackened the reputation of agents who risked their lives to put away Lucas and other drug felons in the 1970s and 1980s.

“I don’t know what these people were thinking, but they are going to pay for it,” he said.

A Universal Pictures spokesman, Michael Moses, said in a written statement that the lawsuit is “entirely without merit.”

“‘American Gangster’ does not defame these or any federal agents,” he said, adding that the corrupt law enforcers depicted in the film were supposed to be New York police officers, not DEA agents.