OKLAHOMA CITY (AP) - Oklahoma's multicounty grand jury is preparing to reconvene to investigate criminal matters.

The grand jury will reconvene Tuesday through Thursday at the Oklahoma Attorney General's Office in Oklahoma City.

The state's 13th multicounty grand jury is led by Assistant Attorney General Charles Rogers, chief of the AG's Multicounty Grand Jury Unit. Thus far, grand jurors have returned 17 indictments, in cases filed in Cleveland, Harper, McClain, Pittsburg and Oklahoma counties.

The grand jury has jurisdiction to investigate criminal matters in all 77 counties. It assists local law enforcement authorities and looks into criminal matters of statewide interest. Each month, grand jurors meet to hear testimony for two or three days.

The nature of the grand jury's investigation has not been made public and all proceedings are closed to the public.