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.

A witness said that Ji did not throw the bomb after activating it, but held it in his hands, Beijing Youth Daily reported.

Ji, a farmer from Heze, Shandong province, said in a blog uploaded in 2006 on sina.com that he was attacked by police in Dongguan at about 3 am on June 28, 2005, while he was carrying a passenger on his motorcycle.

Ji said in the blog that his spine was seriously injured and that he has been paralyzed since then. His passenger, Gong Tao, also was injured in the attack, Ji said. Ji's blog was inaccessible soon after the explosion and it remained so as of Sunday afternoon.

In a statement released at midnight on Saturday, the Dongguan city's public security bureau disputed Ji's accusations, saying that Ji collided with a policeman and was injured when he fell off his motorcycle.

Dongguan police insisted in the statement that he was not attacked by policemen, and it was the accident that caused his paralysis.

However, Chen Xinzhen, news director of Heze's publicity department, said on Sunday that what Ji said in his micro blog was true.

Officials from Ji's hometown went to Dongguan to probe the case in 2006, and Gong, the passenger on Ji's motorcycle, confirmed that they were attacked by the police, Chen told China Daily on Sunday in a telephone interview.

Ji sued the local government of Dongguan in January 2007, demanding compensation of 338,267 yuan ($55,128), but the court denied his request due to a lack of evidence.

Ji appealed to the Dongguan Intermediate People's Court in January 2008, but that court upheld the previous judgment.

In September 2009, Ji went to Beijing and petitioned the Commission of Politics and Law of the CPC Central Committee. The committee required Dongguan's police department to deal with the issue, and in March 2010, the Houjie's public security bureau gave 100,000 yuan to Ji, according to the statement of Dongguan police.

After receiving the money, Ji expressed gratitude toward the Dongguan police and promised not to petition anymore, said the statement.

The explosion caught the attention of netizens on weibo.com, China's most popular micro-blogging platform, with many expressing concerns about social injustice.

"Each unfairly treated person is a potential bomb for the country," wrote Zuoyeben, a renowned micro-blogger who has 6.52 million followers. The post was forwarded more than 7,600 times and commented on more than 6,600 times as of 6 pm on Sunday.

Wang Zhi'an, a commentator on China Central Television, condemned the explosion accident in his micro blog.

"No matter how unfairly you have been treated, if you cross the line, you will be the common enemy of society," Wang said in a post.

On Sunday night, Beijing police reported that they had detained two people who made separate calls to the emergency services hotline 110 on Saturday night, threatening to bomb the airport and a bingo hall. Both were arrested about an hour after the calls. No bombs were found.

Police say the two people had separate grievances and that their bomb threats were attempts to gain attention. Police did not say if the pair's motivations were related to the bombing incident at the airport.

Contact the writers at zhengcaixiong@chinadaily.com.cn and anbaijie@chinadaily.com.cn

Zhao Ruixue in Jinan contributed to this story.