Yakama Nation police found a Sunnyside man's dead body in the trunk of a car south of Toppenish on Friday afternoon.

The Yakima Herald Republic reports the Yakima County Sheriff’s Office is investigating the death of 23-year-old Alberto Gabriel Martinez whose body was found in his girlfriend's green 1998 Honda Civic on Oak Springs Road off of U.S. Highway 97 near milepost 51.

Tribal police notified the sheriff's office after the discovery where, as The Herald states, an autopsy to determine the cause of death has not been scheduled, but is being investigated as a homicide.

The Herald says Martinez was last seen Thursday and his girlfriend's name has not yet been released nor is it known if she has been interviewed yet.

Anyone with information about the case is asked to call the sheriff’s office at 509-574-2500, or Crime Stoppers Yakima County at 800-222-TIPS.