CBS station KCNC-TV in Denver reports retired attorney Tom Miller of Boulder was under investigation by the Jefferson County grand jury.
Miller turned himself in to the Colorado Bureau of Investigation Monday, three days after he was indicted on one count of commercial bribery, a felony punishable by up to three years in prison and up to $100,000 in fines. He was booked and released on a $1,000 bond.
Authorities allege representatives of a tabloid newspaper, which has not been identified, asked Miller to help them buy a copy of the note from Donald Vacca.
Vacca, a former Denver police officer who is an expert in forensic documents, had been asked by Ramsey family attorneys to examine the note, which JonBenet's mother told police she found hours before her daughter's body was discovered.
Authorities say that Vacca, who lives in nearby Evergreen, told them Miller and an unidentified individual approached him on April 1, 1997, and asked to purchase the note. Vacca said he refused and ushered the two men out of his home.
Patsy Ramsey reported finding the 2 1/2-page ransom note on the back stairs of the family's Boulder house early Dec. 26, 1996. It demanded money in exchange for JonBenet, 6.
Several hours later, JonBenet's body was found beaten and strangled in the basement of the home. No arrests have been made in the case.
KCNC-TV reports that Miller is also a former private investigator and handwriting expert. After examining the ransom note, Miller allegedly claimed he believed it had been written in JonBenet's mother's handwriting.
A Boulder County grand jury has been meeting to consider the case for nearly a year.
"I'm interested to see when they're going to indict someone for killing the little girl," said Miller's attorney, Charles Leidner. "Maybe they could find out who killed her and bring them to justice."