This article from May 2016 already mentions AC being involved in the investigation plus how may agencies, etc. were involved.
Five weeks in, Pike County waits and hopes for answers in 8 killings
Soon after learning the magnitude of the slayings and crime scenes, Reader called the Ohio attorney general’s office for help.
Ten crime-scene agents and a supervisor from the Ohio Bureau of Criminal Investigation roared into town to process the four scenes, and most of them would stay for a full 24 hours to complete the work. They came from state offices in Athens, Bowling Green, Cincinnati, Columbus, London and Richfield.
The BCI and the attorney general’s office ended up supplying, at some point or another, 52 special agents/analysts/investigators; 17 workers from the state evidence labs; 11 command staff/supervisors; four support staff members; three special prosecutors; and a victim’s advocate.
As many as 20 state personnel remain in Pike County on any given day, working alongside Reader and his staff members. Ohio Attorney General Mike DeWine is briefed daily during a conference call and travels the 65 miles from Columbus south to Pike County regularly. His most recent trip was Friday, when most everyone involved with the case huddled together for much of the day.
State prosecutor Angela Canepa is on the ground almost every day. She and Matthew Donahue lead the attorney general’s special prosecutions unit, and when there is an arrest, it will be up to them and the Pike County prosecutor to secure a conviction.
DeWine said he remains confident that day will come.