One author of the book, Senator Kaewsan Atibodhi, said the People's Alliance for Democracy (PAD) was preparing to file complaints with the Administrative Court against the Police Special Branch for malfeasance over its actions.

The senator said no part of the book, entitled "Stop The Thaksin Regime, Save Our Country And Democracy" was detrimental to national security, and he would have clarified any matters had the police asked him.

Maj-General Chatchawal Suksomchit, deputy Metropolitan Police Bureau commissioner, said the police committee on publication investigation found the book was not threatening to the country's peace, order and morality.

However, as no publisher was identified in the book it was unlawful to distribute it in public, police told the printing house. They returned the 20,000 copies of the book to the printing house.

Senator Thongbai Thongpao, a human rights lawyer, said the seizure of the book without issuing any charge could be considered a human rights violation. The book was a lawful opinion expressed openly, and the names of its authors were on the back and could be verified. The police conduct was like censorship and theft, and the damaged party could file a lawsuit, Thongbai said.

Police seized copies of the book, written by Bangkok Senator Kaewsan and his twin brother Kwansuang, on Sunday. The 20,000 copies were intended to be distributed to protesters at Government House.

Officers involved did not lay any charges, but claimed they needed to send the book to the Special Branch Police to check if they were detrimental to national security.