HANGZHOU -- Police in east China's Zhejiang Province said Friday they had identified the arsonist as a woman who killed nine people, including herself, and injured two others over gambling grievances on December 13.

Xu Shuiying, 53, was believed to have set on fire an apartment in Quzhou City of Zhejiang on Monday night, according to the police investigation and witnesses, said local police.

Xu experienced financial difficulties due to gambling and bore grudges against those whom she often gambled with, said police.

The fire was lit at about 8 pm Monday in an airtight, ground-floor apartment of an 8-story residential building in Kecheng District, killing nine people at the scene and injuring two others who escaped through a window.

An autopsy report said the nine people died of carbon monoxide poisoning.