State Sen. Robert Regola III has always maintained that a neighbor boy stole his pistol one summer night, then used it to kill himself.

The boy's father, J. Douglas Farrell, yesterday filed a wrongful death lawsuit contending that no such theft occurred. He alleges in the lawsuit that Mr. Regola's teenage son, Bobby, supplied the loaded 9 mm handgun that killed Louie Farrell, 14, then made up a story about the weapon being stolen.

The lawsuit claims it was Bobby Regola, then 16, who possessed and controlled the handgun when he met Louie in the woods behind their houses on July 21, 2006. They planned to smoke a cigar. Instead, Louie ended up dead from a bullet to the head.

Mr. Farrell found Louie's body the next morning. The senator's handgun was nearby.

Eight months later, after an inquest, the Westmoreland County coroner ruled that Louie's death was a suicide.

In the lawsuit, Mr. Farrell names Mr. Regola, his wife, Janette Regola, and their son Bobby as defendants. Mr. Farrell is seeking monetary damages, claiming their negligence caused Louie's death.

Jon Perry, an attorney for Mr. Farrell, said the allegation that Bobby Regola controlled the handgun comes from an investigation done by the Farrell family's legal team.

"We found some additional sources, and some of what we are saying is based on forensic study by experts," Mr. Perry said. "We're not going to disclose our evidence now."

Mr. Regola, 46, a Republican from Hempfield, did not return calls yesterday seeking comment. But in previous interviews, he said Louie Farrell stole the pistol from his bedroom, then used it to commit suicide.

The senator's lawyers also gave that account to a jury in criminal court last summer, when Mr. Regola was tried for gun crimes and perjury. Jurors acquitted him of all six charges after deliberating 3 1/2 hours.

Despite his acquittal, Mr. Regola decided to get out of politics. He ended his re-election campaign a month after the criminal trial, saying he was the victim of character assassination in media coverage of the case.

He will leave office when his Senate term concludes at the end of the year.

His family and Louie Farrell's parents are still next-door neighbors. In previous interviews, Mr. Regola said they once were close friends. He said he wanted to reach out to them after Louie's death, but felt restrained because he knew a civil lawsuit by the Farrells would target him.

One part of suit suggests that Bobby Regola not only supplied the pistol but also may have fired it.

Mr. Farrell claims that Bobby Regola handled the pistol in a reckless manner, permitting it "to discharge into the cranium of Louie Farrell."

Asked if the Farrells were accusing Bobby Regola of actually pulling the trigger, Mr. Perry said: "That is one interpretation. There may be multiple interpretations."

The civil lawsuit makes several of the same allegations that prosecutors did in Mr. Regola's criminal trial.

For instance, it claims that the senator gave the 9 mm pistol to Bobby Regola as a Christmas present in 2003. Bobby Regola was just 14 then, too young to legally own a handgun.

Through his lawyers, Mr. Regola said the pistol belonged to him, not his son. He said Louie Farrell, while in the Regolas' house to care for their dogs, rummaged through the upstairs until he found the pistol in the senator's bedroom.

Mr. Regola did not testify at his trial. He could be compelled to testify in the civil case.