The announcement prompted speculation that Prater would drop the charges against Massey and Ruiz because of insufficient evidence.
A day after OSBI took over, Chance characterized the police investigation as “poor” and said he expected Ruiz to be exonerated.
Solomon also was previously critical of the police investigation, saying “we are confident when the investigation is done properly it will show who is actually responsible.”
OSBI spokeswoman Jessica Brown said Monday that the agency is gathering evidence in the case and is in the early stages of investigation.
“It's going to be a very long process,” Brown said.
In July, Prater's office filed first-degree murder charges against Massey and Ruiz, who prosecutors say planned and carried out the torture killing, according to a probable cause affidavit.
The affidavit revealed that a witness told police she saw Ruiz beat Saunders, tie her to a table and torture her by sawing off her left foot and then trying to cut off her right foot before the saw broke.
The woman told investigators she jumped out of a window to escape after witnessing the killing.
Another woman told police she saw a video of the killing on Ruiz's cellphone and recognized him “as the person in the video cutting off the foot of Saunders,” according to the affidavit.
Massey shared details of the slaying with two detainees while jailed on drug charges, according court documents filed with his murder charge.
Massey admitted to kidnapping a woman and making her watch as Saunders was tortured and killed. Massey also described how Saunders' body was dismembered and left in a field behind the Homeland grocery store at NW 23 and Rockwell Avenue, court records show.