One week after two customers died in a fire in a private room at a luxury sauna facility in Tokyo's Akasaka district, police are investigating the facility's operator for possible professional negligence resulting in death on Sunday (December 21).

An increasing number of shared workplaces are installing sauna baths amid a spike in popularity among workers in their 30s and 40s who view saunas as a place to relax and share ideas. Operators of such facilities aim to help people “recharge,” both physically and mentally while helping them gear up for work.