A 7-year-old girl kidnapped by a guy with a knife late Friday night was rescued within an hour of the kidnap in southwest China's Yunnan Province, said local police Saturday.

The girl and her mother were about to drive home from the Walmart parking lot when the kidnapper sneaked into the backseat and held a knife against the 7-year-old at around 10 p.m., said Yao Zhihong, spokesman of Kunming Municipal Public Security Bureau.

The mother rushed out of the car and called the police, who arrived at the scene at 10:07 p.m. and rescued the girl at 10:48 p.m., said Yao.

The kidnapper planned to rob and demand ransom from the mother. It was probably because his business had failed, said Yao.

The police is investigating the case.