The Oklahoma State Bureau of Investigation is assisting Frederick police in a homicide investigation.
OSBI says police responded to a call around 3 a.m. Saturday for a dead body at a campsite near Frederick Lake.
When they arrived, officers say they found a man that looked like someone ran him over with a car and set him on fire.
OSBI says 54-year-old Tammy Nunn was arrested and booked into the Tillman County Jail for first degree murder.
Agents say the victim has not yet been positively identified.