While police officers armed with rifles guarded a state courthouse today, three Colombians convicted in the machine-gun slaying of a Federal drug informer were sentenced to life in prison.

At least two were working closely with the narcotics division and would have been privy to confidential information provided by drug informers, he said.

He said he shot the brothers because they were drug informers.

Of the drug informer, one senior law enforcement official said, "If we thought he was just somebody going after him because they were just trying to smear his name, we wouldn't take the actions we have."

Body Found in Desert Ravine Mr. Holmes, who was 35 years old, had been accused of ordering two other men to murder a drug informer, Denise Williams, in September 1987.

But after a Boeing 737 crashed on approach to Pittsburgh in September 1994, the F.B.I. spent weeks trying to determine if someone sabotaged the plane to kill a passenger who was a Federal drug informer.

Mr. Kwong, a drug informer seeking leniency on charges against him, had an angry dispute with Ms. Palmer about the way Federal agents were treating him, the prosecution contended.

James Giuffre, a drug informer who became one of the main witnesses against him, said he once confronted the Prosecutor about illegal tactics that Mr. Bissell and his top aides used.

A man who had tried to inject a drug informer with Drano and battery acid and then shot him to death was executed today in the electric chair at the state prison here.

Unlike Mr. Meisel, most drug informers have been involved in some illicit activities and become sources only after being arrested.