It was a murder that shattered a tightly knit suburban neighborhood on Long Island and attracted national headlines for its viciousness.

Kelly Tinyes was stabbed with a World War I bayonet, strangled, slashed, kicked and sexually mutilated by her killer in 1989. The 13-year-old girl's nude body was stuffed in a sleeping bag and stashed in a basement closet, where detectives found it a day later.

A steroids-using bodybuilder who lived down the street was convicted of murder and sentenced to 25 year to life in prison, but the Tinyeses and others insist he could not have inflicted such a brutal attack in his Valley Stream home all by himself.

On Monday, the eve of the 20th anniversary of Kelly's murder, a prosecutor said detectives have uncovered new information that is helping shed more light on the case while putting it back in the public spotlight.

"There's legitimate information that we have uncovered that really has added to the mystery," said Nassau County District Attorney Kathleen Rice, who quietly reopened the investigation shortly after taking office in 2006 and is now going public with the probe.

Rice would not reveal details of new revelations, but it is enough to buoy the Tinyes family.

"I am 110 percent behind her," Richard Tinyes said in an interview at his kitchen table Monday. His wife, Victoria, added: "I'm just glad it went this far to see if something can happen."

Neither Rice nor the family have any doubt that Robert Golub, a 21-year-old bodybuilder described as a "loner," committed the murder on March 3, 1989.

There was talk early in the case that Golub, an admitted steroids user, might have used a "'roid rage defense," still a unique legal proposition two decades ago. Ultimately, however, he denied any involvement in the killing, though he never testified at his trial.

When he was sentenced, Golub finally broke his silence: "I did not kill Kelly Ann Tinyes," he said. "Maybe the person is here today with us, but as sure as there is a God, it is not me."

The killing of the bright, middle-school student also split apart the once-tight street where block parties were the norm and more than two dozen young children frolicked from house to house. The Golubs and Tinyeses each stubbornly refused to leave the suburban street after the killing; each repeatedly accused the other of various offenses that frequently required the police to be called.

The Tinyeses contend that Golub's then-15-year-old brother, John J., had a role in their daughter's demise, but prosecutors and police at the time never accused him of any involvement. Richard Tinyes Jr., who was 8 when his older sister was slain, insists that moments before she was last seen alive, he took a call from someone named "John" who asked to speak with Kelly.

The younger Tinyes cannot say for certain that the caller was John Golub, but he hopes the latest investigation will confirm his suspicions. She left for the Golub home after speaking with "John" and was never seen alive again.

"It wasn't him," insists defense attorney John Lewis, who represents John Golub. "The kid has an airtight alibi. He was playing basketball with his friends." He said his client, who has moved out of state, was cleared of involvement by detectives and prosecutors 20 years ago, and predicted Rice would come up empty in her investigation.

Rice declined to name anyone who might be a suspect, and also would not say whether John Golub had been questioned in the latest probe.

Lewis said that like the Tinyes family, his client has had to live with the suspicions against him for a very long time.

"He just wants to be forgotten."

Victoria Tinyes had a different outlook.

"I just want people to remember a bright, beautiful child."

Had she lived, Kelly Tinyes would celebrate her 34th birthday on Thursday.