The operation was a simple bust-and-buy. An undercover detective, Rodney Andrew, had done it 40 times in five months, working in the New York Police Department’s elite Firearms Investigation Unit.

Ride with the informant to the dealer. Purchase the guns with cash. Then make the collar.

This time, it didn’t happen that way.

The night in March 2003 when Detectives Andrews, 34, and James Nemorin, 36, left to buy a Tec-9 submachine gun in Staten Island would be their last operation. The undercover detectives were murdered by shots to the back of the head and their bodies were dumped near a Staten Island side street.

The execution-style double murder was the first killings of police officers since the terrorist attack on the World Trade Center in 2001, and other than September 11, were the first deaths of two officers in one day in 13 years.

Today, federal prosecutors and the Staten Island district attorney, Daniel Donovan Jr., are unsealing a host of criminal indictments, under a federal racketeering statute, against the six people who have faced state charges in the killings. The alleged triggerman in the slayings, Ronell Wilson, 22, now could be sentenced to death if he is convicted. Wilson was arrested in the Red Hook neighborhood of Brooklyn within a week of the killings.

The five others who were charged with involvement in planning the detectives’ killings are Omar Green,19; Jessie Jacobus, 17; Mitchell Diaz, 16; Paris Bullock, 21, and Michael Whiten, 19. They, too, will be indicted on federal charges today, according to a source in the Staten Island DA’s office. Green, Jacobus, and Diaz have already pleaded guilty to second-degree murder and have implicated Wilson as the triggerman.

The new federal indictments represent an unusual legal strategy in which prosecutors would bypass New York’s state courts – which found the death penalty law to be unconstitutional this summer – to have Wilson stand trial in federal court, where capital punishment is still in effect. Under state law, Wilson, who has pleaded not guilty to charges of first-degree murder, faced a maximum sentence of life in prison if convicted.

Opponents of the death penalty criticized Mr. Donovan and federal prosecutors yesterday for “circumventing” state laws and exploiting a “loophole” in order to seek a high-profile execution. “It’s very troubling that federal prosecutors would impose a death sentence in a state that’s clearly not comfortable with it,” said Marc Jacquand, director of the Anti-Capital Punishment Movement.

A civil-rights attorney and executive director of the New York Civil Liberties Union, Donna Lieberman, said the federal indictments could set a dangerous precedent. “To bootstrap a state crime into a federal offense seems troublesome,” she said.

A capital sentence for Wilson could, however, be a political boon for Mr. Donovan, who inherited an office that had the worst felony conviction rate in the state, and who serves a conservative county with a large population of law enforcement personnel. It would also fulfill a campaign promise. The detectives’ murders took place as Mr. Donovan was running for DA, and he vowed to seek the death penalty for Wilson.

A spokesman for Mr. Donovan declined to comment on the new federal indictments. A spokesman for the U.S. attorney for the Eastern District of New York, Roslynn Mauskopf, did not return calls. A press conference is scheduled for today.