Yamanashi, Japan—Two people were found dead Wednesday inside a retrofitted camper van parked in a remote area of Yamanashi. Emergency services discovered the pair after a concerned family member reported them missing. Preliminary results indicate carbon monoxide poisoning as the cause of death.

The vehicle had been modified to include a portable heating unit for overnight use. Investigators suspect that poor ventilation led to a dangerous buildup of gas inside the enclosed cabin. No signs of foul play were found at the scene during the initial sweep.

Police suggest the heating device was left running while the occupants slept. The camper windows were sealed tightly against the night air. This prevented fresh air from entering the vehicle as the oxygen levels dropped.

Local officials are issuing a warning to outdoor enthusiasts regarding the risks of makeshift modifications. They emphasize the necessity of installing proper ventilation in any vehicle used for sleeping. Portable heaters should never be used in confined, unventilated spaces.

The coroner will perform a full autopsy tomorrow to confirm the toxicology reports. Relatives of the deceased arrived in Yamanashi earlier today to identify the remains. Police are treating the event as a tragic accident.

This incident follows a recent surge in popularity for van-life and modified camping vehicles. Many hobbyists perform their own electrical and heating upgrades without consulting professional installers. Authorities fear this trend increases the risk of similar fatal incidents.

The vehicle has been impounded for a detailed mechanical inspection. Technicians will examine the heating unit to determine if it malfunctioned or was used incorrectly. No other campers were in the immediate vicinity during the incident.

The police precinct handling the case will hold a press conference tomorrow morning. They intend to provide safety guidelines for anyone planning to use heating devices in enclosed spaces. The investigation remains ongoing as they process the final evidence.