Agents from the Oklahoma State Bureau of Investigation and the Payne County Sheriff's Department investigators are working together to solve a homicide case that occurred Sunday evening just outside the Stillwater city limits near the Cimarron Turnpike.

At approximately 6 pm Sunday, 30-year-old James Fields, of Pawnee, was shot multiple times. He was a passenger inside a vehicle when shot. He was transported to Stillwater Medical Center where medical professionals pronounced him dead.

That night, officials arrested Jered Holbrook, 28, of Pawnee, on a first degree murder complaint. Sarah Kelly, 22, of Pawnee, was also arrested on a first degree murder complaint.

On Tuesday, investigators arrested three more people for first degree murder -- Christopher Singleton, 20, his mother Larissa Singleton, 37, and Jeff Pennington, age unknown, all from Stillwater. Agents continue investigating what led up to the homicide.