DUBAI, United Arab Emirates — A retired teacher in Saudi Arabia was recently sentenced to death for his tweets criticizing the country's leadership to his handful of followers, according to rights advocates and his family.

The sentencing of Mohammad Alghamdi, who is in his mid-50s, is the latest in an escalating crackdown on social media users in Saudi Arabia. While others are serving prison terms ranging from 20 to 45 years for their tweets and online criticism of the government, Alghamdi appears to be the first person to be sentenced to death based solely on his posts on X, formerly called Twitter, and YouTube activity.

The wide-scale targeting of critics has unfolded as Saudi Crown Prince Mohammed bin Salman pushes sensitive reforms that have overhauled life and loosened restrictions for many in the country. These sweeping reforms, like allowing women to drive, ending strict gender segregation rules in public and opening the country to entertainment and tourism, have coincided with a similarly sweeping crush of dissent.

Alghamdi, a father of seven living in Mecca, had gained just 10 followers between the two anonymous accounts he ran on X. According to Human Rights Watch, he used the social media site to rail against alleged government corruption, but was mostly resharing posts by more popular government critics.

Twitter accounts targeted

The platform, X, is among the most popular social media sites in Saudi Arabia. It was where Saudis would often go to vent their frustrations with government policies.

Lina Alhathloul, the head of monitoring and advocacy at the ALQST human rights group, says even as users were being targeted and detained for their tweets, the platform remained a kind of final frontier where Saudis could express their views, even if anonymously.

"It was the last space where people were actually discussing social issues," she said. "Everyone in the physical space, in real life, has self-censored themselves. They know they're in danger, but people thought that maybe on Twitter, especially with an anonymous account, they could be safe."

But not even anonymous accounts protected users from Saudi prosecution. It's unclear how Saudi authorities were able to verify Alghamdi's identity on X.

In other cases, it appears the identity of Saudi users may have been leaked, exposing them to arrest and long prison sentences. An FBI complaint and federal investigation in the United States led to the conviction last year of a former Twitter employee found guilty of failing to register as an agent for Saudi Arabia. He was also convicted of taking bribes in exchange for passing along the confidential user data of Saudi government critics.

Alhathloul said the message sent from all these cases is clear.

"You are not safe whatever you do, whoever you are. You just have to muzzle yourself," she said.

She spoke with NPR from exile in Europe. Her sister, Loujain, is a prominent Saudi women's rights advocate who was detained for nearly three years in connection to her activism until her release in 2021. Similar to other activists who've been released in Saudi Arabia, she remains under a travel ban.

Criticism met with counterterrorism law

Alghamdi's case is particularly striking because of the apparently very small reach of his accounts on X in contrast with the severe sentencing he was handed. He can appeal the verdict.

Court documents reviewed by rights activists and Human Rights Watch show Alghamdi was sentenced to death on July 10 under the country's vaguely worded counterterrorism law for using his social media accounts to commit crimes such as insulting the Saudi king or crown prince and supporting a terrorist ideology.

He was found guilty by the Specialized Criminal Court in Riyadh. The court was established 15 years ago to try terrorism cases, but has also been used to prosecute government critics.

What prosecutors often argue in these cases is that insulting or criticizing Saudi Arabia's leadership poses a threat to national security and can destabilize society. Many of these trials happen behind closed doors.

The Saudi government has not responded to an NPR request for comment about Alghamdi's case. However, when officials are asked in public forums about Saudi Arabia's legal and justice system, they've often said the courts are independent or argue that reforming the system as a whole will take time.

A wanted brother

Alghamdi's brother, Saeed Alghamdi, believes the case against his younger brother is actually meant to target him. Saeed Alghamdi is a well-known Islamic scholar connected to many of the kingdom's most prominent jailed critics. He left Saudi Arabia in 2013 and founded the Saudi rights group, SANAD. He now lives in exile in the United Kingdom.

He said Saudi authorities have tried to convince him to go back to the kingdom, promising money and a good life if he returns and stops his activism abroad.

"They want to spite me personally because they tried several times to convince me to return," he said. "When I refused, they resorted to this. That's my read on the situation."

While his claims could not be independently verified, there are known cases of retaliation against family members of dissidents abroad.

"I have absolutely no intention of returning [to Saudi Arabia] as long as the situation remains like this," Saeed Alghamdi said.