However, the documents allege that both parents intended to delay or prevent the arrest of the person who killed their daughter.
The proposed charges were disclosed for the first time in the documents.
Prosecutors at the time declined to actually file charges against John and Patsy Ramsey, who have since been treated as victims in the case.
The district attorney at the time, Alex Hunter, who presented the evidence to the grand jury, said in 1999: "I and my prosecutorial team believe we do not have sufficient evidence to warrant the filing of charges against anyone who has been investigated at this time."
John Ramsey's attorney, Hal Haddon, issued a letter earlier this week opposing release of the indictments, pointing out that Hunter's successor, former district attorney Mary Lacy, cleared the Ramseys based on new DNA testing in 2008.
He also cited Lacy's apology in a letter to John Ramsey at the time, in which she said "no innocent person should have to endure such an extensive trial in the court of public opinion, especially when public officials have not had sufficient evidence to initiate a trial in a court of law."
Another Ramsey attorney, L. Lin Wood, said the indictments that were released are "nonsensical," he said.
"They reveal nothing about the evidence reviewed by the grand jury and are clearly the result of a confused and compromised process," he said.
Patsy Ramsey died in 2006.
Lurid details of the crime and striking videos of the child in adult makeup and costumes performing in pageants propelled the case into one of the highest profile mysteries in the U.S. in the mid-1990s.
The grand jury met three years after JonBenet's body was found bludgeoned and strangled in the family home in Boulder on Dec. 26, 1996.
The Ramseys maintained their innocence, offering a $100,000 reward for information about the killer and mounting a newspaper campaign seeking evidence.
Boulder Police Chief Mark Beckner said the case remains open but is not an active investigation. He predicted the indictment's release wouldn't change anything.
"Given the publicity that's been out there, many people have formed their opinions one way or another," he said.
Former prosecutor and law professor Karen Steinhauser said grand juries sometimes hear evidence that won't be admitted during trial that can form the basis of indictments.
But she added that prosecutors must have a good faith belief that they could prove a case beyond a reasonable doubt before pursuing charges.
"I'm not sure that the release of this indictment is going to change the fact that there has not been able to be a prosecution and probably won't be able to be a prosecution," she said.
David Lane, a defense attorney who was not involved in the case, said the indictments could have been an attempt to force the parents to turn against each other, which he said was unlikely because both were protected by laws that limit testimony of one spouse against another.
"Somebody killed JonBenet Ramsey," Lane said. "It sounds like they were accused of aiding and abetting each other, with the hope someone would crack and break. That didn't happen, and prosecutors may have decided not to go forward."
The Daily Camera reported earlier this year that the grand jury had issued the indictment. The actual documents were released Friday in response to a lawsuit by Daily Camera reporter Charlie Brennan and the Reporters Committee for Freedom of the Press.
Boulder County District Attorney Stan Garnett determined the release would not violate grand jury secrecy rules, and transferred the documents to Robert Lowenbach, a retired Weld County judge, for review.
Lowenbach said Wednesday that only pages signed by the grand jury foreman would be releasable as official actions of the jury. His order mentioned 18 pages in all — nine relating to each of JonBenet's parents. Four pages — two each relating to the parents — were released Friday.
John Ramsey didn't immediately return a call seeking comment.
Patsy Ramsey died of cancer in 2006, the same year a globe-hopping school teacher was arrested in Thailand after falsely claiming to have killed JonBenet. Former District Attorney Mary Lacy cleared the Ramseys in 2008 based on new DNA testing that suggested the killer was a stranger, not a family member.
Lacy did not return a phone call on Friday.
Over the years, some experts have suggested that investigators botched the case so thoroughly that it might never be solved.
Earlier this week, John Ramsey asked officials to release the entire grand jury record if the unprosecuted indictment was made public.
However, Lowenbach said transcripts of grand jury proceedings and evidence presented to it are not considered official action under the law governing criminal court records. He also said releasing such information could hurt other grand juries, whose work is secret.
An attorney representing John Ramsey, L. Lin Wood, has said he's confident that no evidence in the grand jury case implicated the Ramsey family and the public should be able to see that for themselves.