TOPPENISH — The Yakima County Sheriff’s Office is investigating the death of a man whose body was found in a car Friday afternoon south of Toppenish.

The sheriff’s office said in a news release Saturday that Yakama Nation police found the deceased man, 23-year-old Alberto Gabriel Martinez of Sunnyside, in the trunk of his girlfriend’s green 1998 Honda Civic.

The car was located on Oak Springs Road off U.S. Highway 97, near milepost 51.

After the discovery, tribal police notified the sheriff’s office.

Martinez was last seen Thursday night, according to the news release. An autopsy to determine cause of death has not been scheduled, but the case is being investigated as a homicide.

The release did not name Martinez’ girlfriend nor say whether officers had interviewed her.

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