QUJING, Yunnan - Police in Southwest China's Yunnan province have arrested two teenagers suspected of killing seven people, including a pregnant woman, authorities said Friday.

Fu Zhenli, 17, and Liu Qizhi, 18, were detained on September 6 in Shenzhen, Guangdong province, according to police in Qujing city of Yunnan province.

The two teenagers, both from Wugang city of Hunan province, were suspected of killing a pregnant hotel owner surnamed Wu and her two-year-old daughter on August 30 in Fuyuan county, Yunnan province.

Police then found another victim, Tang, who was believed to have been killed by the same criminals.

After being taken into police custody, police learned that the duo had also killed two couples in Hunan and Guangdong provinces in August.

An initial investigation found that the killers, who were classmates in high school, committed the crimes for money.

Further investigation is underway, police said.