GYEONGSAN — A woman died Tuesday after sustaining injuries in an arson attack on an apartment management office in the southeastern city of Gyeongsan last month, raising the death toll to four, police said.

The woman in her 50s died at a hospital in neighboring Daegu while undergoing treatment for burns, according to the police.

The attack occurred on July 23 when an apartment resident, surnamed Ryu, poured flammable material inside the office and set it on fire, injuring eight people, including himself. With the woman's death, four of them have now died.

Ryu, who is in his 70s, has also been receiving treatment for full-body burns and is set to be questioned by police once his condition improves.