A prominent Thai political-science professor who is being investigated on accusations of insulting the monarchy, a crime known as “lèse-majesté,” says that the complaint against him is politically motivated and that he is the victim of a witch-hunt, Channel News Asia reports. Giles Ji Ungpakorn, a professor at Chulalongkorn University, is calling for an international campaign to end the law, which prescribes jail terms for those who criticize the royal family.

Mr. Giles, who was summoned to police headquarters on Monday, is under investigation for his book, A Coup for the Rich. He asserts that during the 2006 military overthrow of the former premier, who was popular among the poor, the Thai monarchy was not as politically neutral as claimed. The professor says lèse-majesté is being used by military and authoritarian elites to protect their own interests.

Insults against the monarchy are taken seriously in Thailand, where the royal family is highly revered. An Australian professor remains in a Thai jail for writing a novel in which a brief passage portrays a crown prince’s private life in an unflattering light.

But rights groups now accuse Prime Minister Abhisit Vejjajivam, who recently took office after months of unrest, of using the law to muzzle his opponents. Earlier this month, several thousand Web sites were blocked after the courts ruled they had insulted the king. —Martha Ann Overland