BANGKOK (AP) — A lawyer says an American citizen has been formally charged with insulting Thailand’s monarchy, which carries a penalty of up to 15 years in prison.

Lawyer Anon Numpa says his client, Joe Gordon, was charged with lese majeste for allegedly translating parts of an unauthorized biography of King Bhumibol Adulyadej and writing articles that defamed the royal family.

Gordon was arrested in May and was detained for the maximum 84 days that a suspect can be held without charge.

The website Prachatai.com says Gordon denied the charge. It says he was born in Thailand but lived in the U.S. state of Colorado for about 30 years before returning to Thailand earlier this year.

U.S. Embassy officials were not available for comment late Thursday.