The US and human rights groups Monday condemned the conviction of a teenage boy in Cambodia over social media messages insulting the ruling party.

Sovann Chhay, who is sixteen and on the autism spectrum, was arrested after making the posts on Facebook and Telegram. He was charged with incitement and insulting public officials. These charges could carry up to two years in prison. He is the son of an imprisoned member of the political opposition. UN human rights experts called for his release in September, after the boy had already been held in pretrial detention for more than two months.

On Monday, the Phnom Penh Municipal Court handed down a sentence of eight months, of which Chhay will serve four and half months in prison with the rest of the sentence suspended. The US ambassador to Cambodia, Patrick Murphy, criticized the sentence. Calling the charges “politically motivated,” he tweeted: “How does jailing the teenage son of a opposition figure demonstrate respect for human rights?”

Phil Robertson, Deputy Asia Director at Human Rights Watch, said in a statement to Reuters: “The conviction against 16-year-old, autistic Sovann Chhay is outrageous and unacceptable on so many levels and signifies a new low in Prime Minister Hun Sen’s witch hunt against his political opponents.”

The court also held that Chhay will be placed on probation for two years following his release.