Guangdong provincial authorities promised on Sunday to look into the alleged unjust treatment of a disabled man who police say set off an explosive device the day before at Beijing Capital International Airport.

The Guangdong Provincial Public Security Department said in a statement that the police must thoroughly probe online allegations that Ji Zhongxing, who set off the homemade bomb, was attacked by police in Dongguan eight years ago.

Ji, 34, who uses a wheelchair, was stopped by security staff when he tried to hand out leaflets outside Gate B of the airport's arrival hall on Saturday evening. Ji then warned people nearby to get away before he set off an explosive device in his bag, injuring himself and a policeman, police said.