A source confirmed the move to ABC News and said that the grand jury will decide whether either of the police officers should stand trial for the 12-year-old's death last November. Cuyahoga County Sheriff Clifford Pinkney has since reiterated the transfer of the findings of their investigation to the prosecutor's office.
Walter Madison, one of the lawyers representing the Rice family, said that they are not happy about the prospect of the proceedings, which are secret.
"This moves from a public process that's transparent to a more secretive one," Madison told ABC News.
The investigation into the shooting, which took place when officers saw the pre-teen at a Cleveland playground holding what they later determined was a pellet gun, has been ongoing since the Nov. 22 shooting.
On May 12, Cuyahoga County Sheriff Clifford Pinkney said that "the majority of our work is complete."