"Some of the men … were interacting and discussing an idea revolving around the possibility of creating a political forum (party)," Matruk al-Faleh said in a statement sent to Reuters.
"The arrests seem to abort the very idea itself," said the politics professor, who was jailed in 2005 over his calls for political reform.
Faleh, now released, said they wanted to "to concretely push the democratic reform movement".
Saudi Arabia is an absolute monarchy dominated by the Saudi royal family, which rules by strict Islamic law. The world’s biggest oil producer and a long-time U.S. ally, it has an unelected quasi-parliament and does not allow political parties.
Three of the 10 men arrested in February are signatories to a petition delivered to King Abdullah and leading princes this week calling for free elections.
Faleh said the rest of the group had intended to sign the petition and that most of them had signed previous petitions in 2003, before King Abdullah took power in 2005.
"The terrorist charge is only a cover-up to hide the real reasons for the arrests, which are to suppress and kill any reform demands," Faleh wrote.
The government has denied the arrests are linked to the petition, which calls for an elected parliament and a constitution based on Islamic principles.
A Ministry of Interior spokesmen said on Tuesday he believed the men were still under investigation. He said the men’s supporters were exploiting media interest in reforms.
A source familiar with the case has said three of the detainees had been involved in collecting money for people recruiting fighters in Iraq.
The petition accuses the government of preventing reformers from travelling abroad, closing Internet sites, banning public demonstrations and threatening state employees with dismissal for expressing opinions contrary to government policy.
There has been no official response to the document.
