South Korean police say a woman in her 20s accidentally set her apartment building on fire while attempting to kill a cockroach with an improvised flamethrower, resulting in one fatality.

According to local media reports, the woman tried to burn the insect using a lighter and a flammable spray, a method she allegedly admitted to having used before. However, the flames spread quickly after household items caught fire on Monday, engulfing other parts of the building in the northern city of Osan.

Police said they intend to seek an arrest warrant for the woman, who may face charges of accidental arson and causing death by negligence.

The blaze claimed the life of a neighbour,  a Chinese woman in her 30s, who lived on the fifth floor with her husband and their two-month-old baby. The couple reportedly opened their window and called for help as thick smoke blocked the stairway. They managed to hand their baby to a neighbour in an adjacent block, but while the husband climbed across safely, the woman fell from the window. She was rushed to the hospital and pronounced dead hours later.

Authorities confirmed that eight other residents suffered from smoke inhalation. The building, which contains commercial shops on the ground floor and 32 residential units above, sustained significant damage.

Police believe the victims resorted to escaping through the window because the stairway was impassable due to heavy smoke.

The incident comes amid growing concerns about dangerous online trends involving makeshift flamethrowers. In 2018, an Australian man accidentally set his kitchen on fire while using a similar method to kill cockroaches.