Ashraf Fayadh, 35, was previously arrested by the country's religious police and charged with apostasy (abandoning one's faith), according to trial documents seen by Human Rights Watch.
One Twitter user even described the decision as ‘ISIS-like', implying the punishment was akin to what is popular with extremists from the Islamic State. Whoever wrote that is probably regretting it already, for Saudi Arabia's justice ministry is planning to sue the "criminal".
"The justice ministry will sue the person who described… the sentencing of a man to death for apostasy as being `ISIS-like'," a justice ministry source told major pro-government newspaper Al-Riyadh.
Neither the user nor the possible penalty were identified, but last year three lawyers were sentenced to up to eight years in prison by a Riyadh Saudi court for a similar "crime".
"Questioning the fairness of the courts is to question the justice of the Kingdom and its judicial system based on Islamic law, which guarantees rights and ensures human dignity," the source told the newspaper.
According to the Syrian Observatory for Human Rights, the self-proclaimed Islamic State group may be responsible for executing around 10,000 people, though it will hardly ever be possible to give an accurate number.