Mr. Pettit has built a reputation for building homicide cases on the testimony of prisoners and informants, a practice that led the state Superior Court to order a new trial for one of two men convicted in the 1992 beating death of East Washington insurance adjuster Robert Hannen.

The appellate court overturned the conviction of Lawrence Barnes, citing evidence that one of Mr. Pettit's witnesses was in state prison the night that he said he had observed the defendants in Washington. Mr. Pettit then decided to grant the other defendant, Rodney Yarbor, a new trial.

Rather than risk jury verdicts, the two men accepted plea agreements that kept them in prison about two more years. But they accused Mr. Pettit of prosecutorial misconduct, saying he should have known one of his key witnesses was in prison and could not have seen what he claimed.

Mr. Pettit also had a protracted civil court battle with Frederick Brilla, a convicted drug dealer and one of two men shot dead in a North Strabane tavern in November 2003.

Mr. Brilla sued Mr. Pettit in federal court for refusing to return possessions seized during a pair of drug raids in 1989. A jury held Mr. Pettit personally liable and ordered him to pay $65,000 in punitive damages.