Three people were killed and 15 others injured in a knife attack at a supermarket on Monday in Shanghai, China, local police authorities said Tuesday, reports Xinhua news agency. The police received a report of the incident at 9:47pm local time and quickly arrived at the scene. The attacker, a 37-year-old man surnamed Lin, was apprehended on the spot after the police arrived. The 18 victims were immediately sent to the hospital for treatment. Among them, three died despite rescue efforts. According to investigation, the man had committed this attack in order to vent his anger on someone due to personal financial problems.