Frustration over online gambling debts prompted a 29-year-old man to carry out the crude bomb attack inside Shanghai airport that injured five people, including the attacker, police said on Monday.
The attacker, identified as Zhou Xingbai from Guizhou region in southern China, was seriously injured when he slashed his throat after lobbing the home-made bomb into a crowd of passengers near a check-in counter inside Terminal 2 of the busy Shanghai Pudong international airport on Sunday.
The others injured were three Chinese nationals and a Philippines citizen.
According to the version of events shared by Shanghai police, Zhou planned the attack well in advance. On Sunday, he took a long-distance train from a city neighbouring Shanghai and reached the airport at 2.30 pm.
He was carrying a beer bottle filled with crackers, police said. Once at the airport, he chose a place, lit the crackers and threw the bottle into the crowd.
Investigators found remains of the crackers in a rented house at Kunshan near Shanghai, where Zhou had stayed before taking the train to the city.
Police said he had accumulated online gambling debts over the years while working in an electric company. Subsequently, he lost all his money, borrowed from friends and lost that money too. Before carrying out the attack, Zhou said in a WeChat - a popular mobile social media app - group that he was in "heavily in debt", had planned to do something "crazy" and was ready to die.
Police did not specify how much debt he had incurred.
There have been a few instances in China in the recent past where personal problems or a sense of injustice against local authorities have triggered acts of violence by lone attackers.
In July 2015, a man in northeastern China set himself alight after launching a knife attack in a government building, killing one person and injuring another. Grievances against the local government apparently triggered the attack.