A woman in her 30s died after saving her two-month-old baby from a fire accidentally started by a neighbor attempting to kill a cockroach using a lighter and spray in Osan, Gyeonggi Province, police said Monday.

According to Osan Police Station, the fire broke out around 5:35 a.m. Monday in a mixed-use building where a woman in her 20s, identified only by her surname A, lived on the second floor.

She tried to kill a cockroach by spraying flammable mist and igniting it with a lighter, effectively creating a small flamethrower.

Flames quickly spread to a nearby bed and piles of trash, prompting A to call emergency services. Firefighters extinguished the blaze within about 40 minutes.

The fire, however, claimed the life of a Chinese woman in her 30s, identified as B, who lived on the fifth floor. Eight other residents suffered from smoke inhalation.

When the flames erupted, B and her husband opened a window to call for help, holding their infant child. Because the building stood less than a meter away, neighbors were able to reach out from their window and safely receive the infant. B’s husband also managed to escape through the window to the neighboring building.

B fell while attempting to climb across and sustained severe injuries. She was taken to Ajou University Hospital but was pronounced dead around 10:40 a.m., about five hours after the incident.

Police believe the couple resorted to escaping through the window because thick smoke prevented them from safely using the stairs.

Authorities said they plan to seek an arrest warrant for A on charges of accidental arson resulting in death and injury.