They have filed additional charges against suspect Craig Wood.
The amended charges were filed with the court Monday, after final autopsy results were received.
Wood is now charged with murder, armed criminal action, child kidnapping, rape and first degree sodomy.
Hailey Owens was grabbed off the street near her home in Springfield on February 18. Her body was found a few hours later in the basement of Wood's home.
A hearing is set for this Thursday, April 24, on the amended charges.