A woman reported missing by her family was found dead in the back of a police vehicle in Hadong, South Gyeongsang Province, Saturday.

In an unexpected turn of events, local police revealed Sunday that she appeared to have entered the empty, parked car for unknown reasons and was unable to get out for 36 hours amid blistering heat, leading to her death.

The backseat doors of police vehicles cannot be opened from the inside, a feature designed to prevent suspects from escaping. The front seats are also separated from the back by a partition, the Hadong Police Station explained.

Surveillance footage shows the victim entering the unlocked vehicle in the police station’s parking lot through a back door at around 2 a.m. Friday. The car had remained unused until the time of her discovery, at around 2 p.m. Saturday, by a police officer.

The victim’s family had reported her missing three hours before her discovery.

Given that there were no apparent signs of foul play, authorities are considering her death may be related to heat-related illness.

The region has been under a heat wave warning at the alert level since July 23, with daily temperatures reaching a high of 34 degrees Celsius on Friday and Saturday.

Further investigation is underway to determine the exact cause of her death and why she had entered the car.