The Thai government filed a criminal complaint against political leader Thanathorn Juangroongruangkit Wednesday, citing crimes against the monarchy.

Juangroongruangkit is the leader of Future Forward, a pro-democracy party created to contest Thai elections. He criticized the government’s administration of recently developed COVID-19 vaccines. Juangroongruankit specifically condemned the government for relying too heavily on the Crown Property Bureau, a company owned by the monarchy.

Prosecutors filed the complaint under Thailand’s Lese Majeste Law. The statute prohibits any individual from defaming, insulting or threatening the monarchy. Though only occasionally applied in decades prior, the law has been increasingly used against political opponents and to stifle dissent.

This is not the first time Juangroongruankit has faced criminal prosecution. After Future Forward had a strong showing in the March 2019 elections, the government filed a criminal complaint against the leader, stating that he “raised unrest and disaffection amongst the people in a manner likely to cause a disturbance in the country.”

If convicted of Wednesday’s charges, Juangroongruangkit could face up to 15 years in prison.

In response to Wednesday’s complaint, Juangroongruankit asserted that individuals in Thailand have a right to speak out against the government.