All but one of the victims' remains have been exhumed from the site, prosecutors said. They had a total 178 wounds inflicted by firearms.
More than 100,000 people died during the war in Bosnia, which erupted when the country's Serbs rebelled against independence from the former Yugoslavia and moved to create their own state.
The Serbs took control of over two-thirds of Bosnia in the early days of the conflict, expelling and killing non-Serbs - the Bosniaks, who are mostly Muslims, and Bosnia's Croats.
The suspects detained Wednesday were members of the so-called “crisis committee” that was formed when Bosnian Serbs took control of the area in 1992.
Also among the suspects is Gen. Radislav Krstic, who is serving a 35-year-old prison sentence. In 2004, he was convicted by the U.N. war crimes tribunal for the former Yugoslavia on charges of aiding genocide. Bosnian prosecutors said he will be questioned in prison in Poland.
Another, unidentified suspect lives outside Bosnia, and authorities plan to seek his extradition, the prosecutor's statement said.