The suspect, a 35-year-old native of Xihua County in central China's Henan Province surnamed Zhu, sought revenge on society due to his addiction to online games, adversities in work and life, and conflicts with his employers, which gradually led to his alleged personal grievances and dark mind.
According to the police, Zhu have been away from home since dropping out of middle school, and have worked to earn his living in a number of provinces including Henan, Jiangsu and Hebei.
He has been jobless since resigning at the end of 2017 from a factory in Langfang, north China's Hebei Province, investigation showed.
The Beijing police thanked the employees at the mall and restaurants therein, as well as passers-by on the scene who helped with their work, and suggested citizens ensure their own safety before helping those in jeopardy.
At around 1 p.m. on Sunday at Joy City in the commercial area of Xidan, Xicheng District, Beijing, Zhu launched the knife assault, resulting in one death and 12 people injured. Police found all of the victims were strangers to the suspect.
None of the injured are in critical condition, and five have already left hospital.
The suspect is under criminal detention at the moment as investigation goes on.