A group of boys on bicycles gather on a dusty side-street in easternSaudi Arabia. Foot on pedal, 10-year-old Murtaja Qureiris is about to lead the group of around 30 children.

In video footage obtained by CNN, he is wearing rolled up denim jeans and black flip-flops on his feet, and grinning at the camera recording the event. It may look like a regular bike ride, but the group is staging a protest.

Moments after they set off, Qureiris gets lost in the sea of boys, struggling to keep up as he lifts a megaphone and presses it against his lips. “The people demand human rights!” he shouts.

As a boy, Qureiris participated in demonstrations like this bike ride, expressions of dissent inSaudi Arabia’s Eastern Provinceduring the 2011Arab Spring.

Three years after he was filmed taking part in the bike protest, Saudi authorities arrested Qureiris, then just 13 years old.

He was traveling with his family to Bahrain when he was detained by Saudi border authorities on the King Fahd causeway that connects the two countries.

At the time, he was considered by lawyers and activists to be the youngest knownpolitical prisoner in Saudi Arabia.

Now, at the age of 18, Qureiris is facing the death penalty after being held for almost four years in pre-trial detention, CNN has learned.

Recall that in April,Saudi Arabia announced it had executed 37 menwho, according to rights group Reprieve, were mostly from the kingdom’s Shia minority. The country has one of the highest rates of execution in the world, and has frequently been criticized by rights groups forexecuting people who were minors at the timeof the commission of crimes.

Qureiris was 10 years old when he committed at least one of those alleged crimes in his charge sheet, CNN has learned. He was charged with accompanying his activist brother, Ali Qureris, on a motorcycle ride to a police station in the eastern Saudi city of Awamiya, where Ali allegedly threw Molotov cocktails at the facility.

The age of criminal responsibility in Saudi Arabia is unclear, but in 2006 the kingdom told the Committee on the Rights of the Child that it had raised it to 12,according to Human Rights Watch.

Saudi Arabia has also previouslytold the United Nationsthat it does not impose the death penalty on prisoners convicted of crimes before the age of criminal responsibility.

Qureiris is currently being tried at a terror court, where the prosecution has accused him of belonging to “an extremist terror group.” He faces other charges ranging from violence allegedly committed during protests – including helping to construct Molotov cocktails — to shooting at security forces and marching at his brother’s 2011 funeral.

Qureiris has denied the charges and said that the confessions, which the prosecution has largely relied on, were obtained under duress, CNN has learned.

Saudi Arabia has not responded to CNN’s request for comment on his case.

Minors at the time

If Saudi Arabia sentences Qureiris to death, he would join at least three other prisoners executed this year for crimes allegedly committed before the age of 18.

CNN reviewed court documents that detailed the cases of two of three men who were minors at the time of the commission of alleged crimes. Abdulkareem al-Hawaj, Mujtaba al-Sweikat and Salman Qureish were part of the mass execution of 37 men, most of whom were Shia.

All three were arrested for violence the government says was committed during protests around the time of the Arab Spring. But the prosecution relied heavily on confessions which the prisoners said were extracted from them. In the court proceedings, they said that they were tortured, the confessions made under duress.

In Saudi Arabia, the death penalty can only be enforced by order of King Salman or his authorized representative. Crown Prince Mohammed bin Salman is frequently characterised as the King’s deputy.

The unmasked protester

A crackdown on Saudi dissidents has intensified since 2015, when King Salman ascended the throne, appointing his son, Mohammed bin Salman, to several powerful posts. The young prince has spearheaded a drive for social and economic reforms in the kingdom, and has sought to consolidate his rule in the process.

The 33-year-old crown prince has ordered the rounding up of scores of high-profile clerics, analysts, businessmen and princes, as well aswomen’s rights defenders who were allegedly torturedand whom authorities accuse of having “suspicious contact” with foreign entities. The Saudi government has repeatedly denied allegations of torture.

In one of the videos of Murtaja Qureiris obtained by CNN, the boy is seen standing next to his father who is addressing a crowd of protesters.

Most of the demonstrators are masked. Murtaja and his father are barefaced, something that may have made it easier for the family to become ensnared in the government’s crackdown on activists.

“Murtaja (Qureiris) was one of the only people who didn’t wear masks during the protests,” recalled activist Mohammad Daman. “And he was always with his dad (Abdullah).”

In the footage, Abdullah is dressed in a brown thobe normally reserved for the elders of an Arab tribe, and speaking into a megaphone while another protester holds a Quran over his head.

“We pledge to the martyrs that we will continue our marches,” says Abdullah Qureiris.

Standing next to him is Murtaja Qureiris with a ski mask on his head, having apparently removed it from his face. He glances at the camera, smiles, and walks away, unaware of what was to face him in the future. (CNN)