NEW TAIPEI CITY, TAIWAN — Police responded to a strange call earlier this week, involving an idling parked car and a middle-aged couple found in the backseat.

On the morning of May 2, a woman was contacted by her sister’s employer, informing her that her sister had not shown up for work. The woman notified police, who went searching for her sister.

Officers later found the woman’s sister later that evening, dead in the backseat of a BMW parked by the side of a road. When the cops smashed the windows to look inside, they found the woman with her face in a man’s lap. The man had only a shirt on.

Given that the car was idling, police believe the couple may have died of hypoxia as a result of poor air circulation, or carbon monoxide poisoning. No signs of foul play have been reported.