Three people were killed and 15 others injured in a knife attack at a suburban supermarket in Shanghai on Monday on the eve of China's week-long National Day holiday, the latest in a series of stabbing incidents in major Chinese cities this year.
The assailant, a 37-year-old man surnamed Lin, has been detained, local police of Songjiang district said in a statement on Tuesday.
According to an initial investigation by police, Lin had travelled to Shanghai to vent his anger following a personal financial dispute.
The knife attack came one day before China's National Day "Golden Week", when holiday travel was expected to surge.
Public stabbing incidents have risen over the years in China, with authorities often putting the blame on mental illness. Children at schools are a common target.