A Colorado grand jury voted to indict the parents of slain child beauty queen JonBenet Ramsey more than 13 years ago, but prosecutors reportedly refused to go forward on the case, according to the Boulder Daily Camera newspaper.

The grand jury voted in 1999 to indict John and Patsy Ramsey on charges of child abuse resulting in death, three years after their 6-year-old daughter was bludgeoned and strangled in the basement of her family's house on Christmas Day.

But former Boulder County District Attorney Alex Hunter declined to sign the indictment, believing he could not prove the case beyond a reasonable doubt, the Daily Camera reported.

"I and my prosecution task force believe we do not have sufficient evidence to warrant the filing of charges against anyone who has been investigated at this time," Hunter told reporters in October 1999.

"Child abuse resulting in death" is a Class II felony punishable by up to 48 years in prison, according to the Daily Camera.

"We didn't know who did what," a juror told the Daily Camera on the condition of anonymity. "[B]ut we feel the adults in the house may have done something that they certainly could have prevented, or they could have helped her, and they didn't."

Hunter, who left his post in 2008 after 28 years as district attorney, declined to discuss the grand jury's decision, according to the Daily Camera.

But in a 2001 interview with NBC News, Hunter said he had no regrets about his decision not to charge anyone.

"I have enough people that I respect that have said to me, 'You know, you made a tough call, you made a call the public didn't like. But you were true to the law, you were a good prosecutor, and that's plenty for me.'"

Lin Wood, John Ramsey's attorney, backed up Hunter's decision in a statement to NBC News.

"The DNA tests performed after the time of the Boulder grand jury not only prove the Ramseys to be innocent and the grand jury wrong, they also make D.A. Alex Hunter a hero who wisely avoided the miscarriage of justice," Wood said.

Patsy Ramsey died of ovarian cancer in 2006. The couple and their older son, Burke Ramsey, were exonerated in the case in July 2008, even though they were never formally charged in connection with JonBenet's death.

"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," former Boulder County District Attorney Marcy Lacy wrote in a letter to John Ramsey in 2008. "No innocent person should have to endure such an extensive trial in the court of public opinion."

Ramsey family via AP, file

This image made from an undated family video shows JonBenet Ramsey performing during a beauty pageant.