Conversation so far:
when was Chen Guangcheng detained?
On 7 September 2005, while Chen Guangcheng was in Beijing, he was reportedly abducted by security agents from Linyi and held for 38 hours.
why was  Chen Guangcheng detained?
Chen Guangcheng said that authorities threatened to levy criminal charges against him for providing state secrets or intelligence to foreign organizations.
when did Chen Guangcheng's trial start?
On 24 August 2006, Chen Guangcheng was sentenced to four years and three months for damaging property and organizing a mob to disturb traffic.
did Chen Guangcheng win the trial?
On 24 August 2006, Chen Guangcheng was sentenced to four years and three months for damaging property and organizing a mob to disturb traffic.
who was Chen Guangcheng's attorney?
Chen Guangcheng had three lawyers, including Xu Zhiyong of the Yitong Law Firm.

Question: why was he detained
Self-contained rewrite: why was Chen Guangcheng detained?