Sgt. Chris Widmer says Pima County Sheriff's deputies found the body of Thomas C. Pimper on Saturday around 7:10 p.m.
According to the Pima County Sheriff's Office, Pimper was in his Honda Civic, which was parked on the southernmost end of South Old Nogales Highway.
Widmer did not say how Pimper died.
Authorities say Pimper was last seen Tuesday night when he left his home near Speedway Boulevard and Country Club Road to go to a Circle K store.
Family members had told police Pimper suffered from a medical condition that required daily prescription medication.
They say he left without medication, his wallet or cellphone.