File photo.

Authorities are investigating the death of a 34-year-old police officer whose body was found Tuesday inside a locked police vehicle in the Athens suburb of Agios Dimitrios.

The officer had been missing since Sunday night, when he left the Neos Kosmos home he shared with his 38-year-old partner, also a police officer. She reported him missing Monday morning after he failed to answer calls or report for duty.

His phone led colleagues to the vehicle, where he was found in the driver’s seat with an empty liquor bottle between his legs. A heated argument prompted him to leave home before he disappeared.

A medical examiner found neck abrasions possibly from contact with another person and estimated death occurred 10 to 12 hours before discovery, citing severe pulmonary edema linked to alcohol and heat. Toxicology results are pending. He served in an Athens narcotics unit.