Shenzhen police arrested three men suspected of being involved in planting a bomb in a restaurant in Dalang Subdistrict on Monday.
The bomb exploded at 10 p.m. Monday but there were no casualties.
One of the suspects, identified only as Wu, allegedly admitted to making the bomb with gunpowder from firecrackers and placing it in the restaurant restroom, the Southern Metropolis Daily reported Thursday.
After failing to extort 20,000 yuan (US$3,037) from the restaurant owner, Wu, 34, allegedly detonated the bomb.
The Guangdong native graduated from the electronics department at a technical school in 2000 and was later seriously burned in a factory accident.
Wu said he had been unable to find another job because of his injuries and his claim for compensation from the factory over the past 10 years had been unsuccessful, the paper said.
Wu met another suspect, identified only as Li, on the Internet, who had also complained about the job situation.
The two men later came up with the idea of making money through extortion. The idea became reality when the third suspect, Qin, joined them.
They chose the restaurant at random and Wu bought enough gunpowder from Huizhou to make two bombs. One was placed under a water basin in the restroom, the paper said.
We never intended to hurt anyone, Wu said.
Police arrested Wu and Li in their rented apartment in Bantian in Longgang District on Tuesday night. Qin was found in an Internet cafe in Futian District.
The restaurant owner, Liu, reopened the restaurant Tuesday saying he had installed cameras to monitor diners.
(By Li Hao)