Serial petitioner Srisuwan Janya on Wednesday asked the Anti-Money Laundering Office (Amlo) to investigate 11 people he believes are helping finance the anti-government demonstrations.
The secretary-general of the Association for the Protection of the Constitution submitted a petition to Amlo, with the 11 names.
Mr Srisuwan said they had provided material and financial support for past demonstrations, and for the planned protest by the United Front for Thammasat and Demonstration planned to start this Saturday at Thammasat University's Tha Prachan campus.
He asked Amlo to exercise its power and order banks to reveal bank accounts opened by the 11 people, or other groups of people, to receive donations supporting the protests, which were illegal.
Mr Srisuwan said numerous protests had been organised both in Bangkok and other provinces, outside and inside academic compounds. A number of core leaders of the protests had been summonsed by the police, charged with various legal offences and released on conditonal bail.
After being released, they continued to take an active part in other demonstrations in various provinces in violation of their bail conditions, and declared they would lead a major demonstration on Sept 19-20.
"The demonstrations would not be possible without interested groups acting as a feeding pipeline from behind. Every public gathering needs a lot of money to pay for food, water, the stage, sound system, mobile toilets, equipment and labour costs," he said.
"It would be difficult for students, most of whom do not have any income of their own, to pay for the protests by themselves.
"Many people have opened bank accounts to accept donations online to support the protests," Mr Srisuwan said. "They include actors, actresses, businessmen, film directors and other groups of people."
Although it was obvious the past demonstrations were illegal, the authorities had not taken legal action against their supporters, who might have also violated the Anti-Money Laundering Act of 1999 and its amendments, according to Mr Srisuwan.
Those people might have also violated sections 83 and 86 of the Criminal Code by supporting illegal activities, he said.