An “escape room” experience became a literal nightmare after five teen girls perished in a fire after becoming trapped while participating in the activity Friday in Poland. Escape rooms are a form of entertainment where those who go inside of a locked room unveil hints and clues in order to get out or “escape.”

The Associated Press reported that a “faulty heating system” was to blame for the blaze that left five 15-year-old girls dead while celebrating one of the girl’s birthdays at the venue, located in the city of Koszalin.

Officials reportedly concluded that the teens’ cause of death was due to “asphyxiation,” in other words being suffocated to death from inhaling fumes—in this case carbon monoxide.

“Preliminary findings suggest that the fire was caused by an unsealed gas container inside a heater,” Koszalin prosecutor Ryszard Gasiorowski told the news outlet.

A report published Sunday by the AP said a man, identified as “Milosz S.” by officials, is being held in the case. He reportedly designed the venue, located in a private dwelling where there were apparently no emergency exits to ensure the teens could’ve safely escaped.

Prosecutors charged Milosz S. with “intentionally creating a fire danger and unintentionally causing the deaths of the girls.” Court officials are reportedly asking that the suspect to be detained for three months as the investigation continues. A decision is expected to be made regarding the request on Monday.

Also believed injured in the catastrophic event was a 26-year-old male employee of the entertainment site, who officials said suffered unspecified burns. Though the extent of his injuries haven’t been revealed, the man was apparently unable to immediately speak with investigators regarding the incident.

Gasiorowski said the teenagers became trapped after the fire ignited “in a part of the detached house that was being used as a reception room,” which meant that employees were not able to get to them.

Thirteen other escape rooms in the country have reportedly been shut down in the wake of the tragedy, with “safety flaws” being cited as the reason for the closures.

[Feature photo: Pexels]