Police Chief Mark Beckner confirmed Monday his department's only involvement in the case would be to provide new leads to prosecutors or provide assistance if requested.
The decision to shift the investigation to the district attorney's office helped avoid a lawsuit by JonBenet's parents, John and Patsy. Their lawyer, L. Lin Wood, had said police ignored leads and tips about the Dec. 26, 1996, slaying.
"I suspect this is unprecedented in modern law enforcement to have an unsolved active investigation taken away from a police department," Wood said in a telephone interview from Atlanta.
The Ramseys have denied any involvement in JonBenet's death, saying an intruder killed their 6-year-old daughter. They moved to the Atlanta area after the slaying.
Newly elected District Attorney Mary Keenan agreed in December to reopen the investigation and focus on new leads.
"We will not exempt the Ramseys from this investigation," she said in a Dec. 20 letter to Wood. But she also told Wood she believed "the Boulder Police Department has done an exhaustive and thorough investigation of the Ramseys as potential suspects."