In what may be a violation of the Constitution’s prohibition against double jeopardy, federal prosecutors in Brooklyn are seeking the death penalty against a drug dealer for killing a man in a housing project in 1999.

The drug dealer, Gerard Price, was acquitted of that crime during a 2001 trial in state court, where his lawyer claimed that Price had acted in self-defense.

It’s conceivable that Price would have been better off had he been convicted in 2001; the Brooklyn district attorney, Charles Hynes, who was prosecuting him then, wasn’t seeking the death penalty as the U.S. attorney, Benton Campbell, is now. Legal experts could not recall a single similar case in which federal prosecutors have retried an acquitted man, and sought his death, where state prosecutors had not.

Over the last three years, federal prosecutors have either sought the death penalty or said they would against about a dozen defendants under indictment for murders in Queens, Brooklyn, and Staten Island. This rise in death penalty proceedings in Brooklyn has caused controversy, and delayed for about half a year the nomination to the bench of a former U.S. attorney in Brooklyn, Roslynn Mauskopf.

The Price case has received far less attention than the other capital murder charges in the U.S. Courthouse in Brooklyn.

Price, a reputed member of the Bloods street gang, faces several charges in the federal indictment, ranging from four attempted murders to dealing heroin and crack cocaine near the Gowanus Houses. One of the charges carries the prospect of the death penalty: murder in aid of racketeering. Price is charged with murdering an acquaintance, Ronald Chavis, and shooting in the face another man, Michael Brown, during a single act of violence.

At the state trial, Price’s attorney, Howard Greenberg, argued that the shooting happened after Price had taken a gun away from Chavis during an elevator ride. Mr. Greenberg asserted that Chavis and Brown were trying to kill Price.

“Simply put,” Mr. Greenberg, said at the time, “this is a case of self defense.” The jury acquitted Price, who did not testify in his own defense, of second degree murder. The gun was never found. Testimony suggested that Price had taken a nap immediately after the shooting.

Since the acquittal, Mr. Price has pleaded guilty to federal drug charges and is currently in prison. His name featured frequently during the drug trial of his older brother, Robert Price. Testimony from that trial apparently implicated him in at least three attempted murders.

It is unclear what new evidence the federal government has uncovered in the Chavis murder. The only eyewitness to the shooting, Brown, who was shot himself, never testified in the state trial. Brown is currently incarcerated in federal jail, raising the possibility that he will testify at Price’s coming trial.

Legal precedent suggests that the federal government has wide authority to retry defendants who have already been tried in state court.

Lemrick Nelson was convicted in federal court of stabbing a chasidic Jew during race riots in Crown Heights in 1991 after a state court had acquitted him. There have also been both state and federal trials in crimes ranging from the Rodney King beating to the Oklahoma City bombing.

One legal expert said it is an open question if the federal government can retry Price for the same alleged facts on a nearly identical legal theory, without violating the Constitution’s prohibition against double jeopardy.

“I think this would certainly be challengeable on federal constitutional grounds,” the director of the Death Penalty Information Center in Washington, D.C., Richard Dieter, said. “He was dragged into court on that same set of facts and acquitted, and that’s what double jeopardy is all about.”

A professor at Chicago-Kent College of Law, David Rudstein, said the federal charges against Price do not violate the prohibition against double jeopardy.

“The federal government is treated as a totally different entity as the state government,” Mr. Rudstein, who has written a book on double jeopardy, said.

The lawyer representing Price against the federal charges, Bobbi Sternheim, could not be reached for comment.

“If ever a case cried out for federal prosecutors to take a pass on at least seeking the death penalty — never mind prosecuting the case — this is that case,” the lawyer who won Price’s acquittal, Howard Greenberg, said in a phone interview.

The federal trial of Price is still a year away and the question of double jeopardy does not appear to have come up in court. But the judge, Nicholas Garaufis of U.S. District Court in Brooklyn, has requested that Attorney General Mukasey reevaulate the Justice Department’s decision to seek the death penalty. Judge Garaufis has given no indication of what prompted him to make that request, saying during a public court hearing, “I’m agnostic about the outcome.”