BOULDER, Colo. — Prosecutors announced today that new DNA tests have cleared JonBenet Ramsey’s family in the 1996 killing of the 6-year-old beauty queen, finally freeing them from the “umbrella of suspicion” that has lingered for more than a decade.

The Boulder County district attorney, Mary Lacy, said today the tests point to an “unexplained third party.” She released a copy of a letter she sent to John Ramsey today that said: “To the extent that we may have contributed in any way to the public perception that you might have been involved in this crime, I am deeply sorry.”

Ms. Lacy said prosecutors don’t consider any member of the Ramsey family to be a suspect.

For years after the slaying, checkout-aisle tabloids and crime shows went after the couple. News reports cast suspicion on JonBenet’s older brother, Burke. Boulder police investigating the murder said the parents were under an “umbrella of suspicion.”

Ms. Lacy has previously expressed doubts that the parents were involved. In 2003, a federal judge handling a defamation lawsuit at Atlanta involving the Ramseys said evidence in the case was more consistent with the theory that an intruder killed JonBenet, not her parents, and Ms. Lacy said she agreed.

Mr. Ramsey found his daughter’s strangled and bludgeoned body in the basement of the family’s home at Boulder on Dec. 26, 1996. Patsy Ramsey said she found a ransom note demanded $118,000 for her daughter.

Mr. Ramsey, a software entrepreneur, has said in interviews he believes the case will be solved.

Patsy Ramsey died June 24, 2006 of ovarian cancer at the age of 49 in Atlanta, where the family moved after JonBenet’s death.

Less than two months after Patsy Ramsey died, the case appeared to blow wide open with the arrest at Thailand of John Mark Karr, a sometime teacher obsessed with the little girl’s slaying. Mr. Karr made bizarre, detailed confessions to the killing, but authorities said DNA evidence showed Mr. Karr did not commit the crime.