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 in Saudi Arabia’s Eastern Province during the 2011 Arab 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 known political 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.

‘Sowing sedition’

In April, Saudi Arabia announced it had executed 37 men who, 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 for executing people who were minors at the time of 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 previously told the United Nations that 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.

Murtaja Qureiris was 11 when his brother died taking part in protests that the kingdom described as violent.

In videos of the older Qureiris brother’s funeral obtained by CNN, mourners chanted anti-government slogans as the procession filled a thoroughfare.

The video showed the slain activist’s father, Abdullah Qureiris, leaning over the shrouded body, openly pleading with God to help him deal with the absence left behind by his son’s death. He is seen kissing him one last time before the body is carried away by a sea of mourners.

Though the prosecution has not held Qureiris responsible for any loss of life, CNN has learned that it is seeking to impose the harshest form of the death penalty, which may include crucifixion or dismemberment after execution. Prosecutors argued that his “sowing of sedition” warranted the worst possible punishment, according to the kingdom’s strict interpretation of Islamic Sharia law.

A charge sheet recommending the death penalty was presented to Qureiris just months before his 18th birthday. Another of his brothers has also been jailed, and his father was detained last year, according to activists.

At least one year and three months of Qureiris’ detention has been spent in solitary confinement, CNN has learned.

‘Extracted confessions’

In 2016, the UN Working Group for Arbitrary Detention discussed the case of a jailed Saudi minor whom it did not name, but whose information matched the details CNN collected about Qureiris.

His birthdate, as well as his place and date of arrest, were consistent with Qureiris’ case.

The UN Working Group said at the group’s 77th session on November 2016 that it believed the minor had been tortured, his confessions “extracted” and that his arrest was arbitrary. It also said that the detention violated international norms, according to its published findings.

The UN Working Group said the minor was likely detained in connection with “his participation in peaceful demonstrations calling for justice for some protestors who were killed and in the funerals of those martyrs.”

The UN Working Group for Arbitrary Detention and the UN Special Rapporteur for Torture did not respond to CNN’s request for comment on the case.

UK-based Saudi activist Mohammad Daman, who was present at several 2011 protests Qureiris participated in, told CNN the demonstrations were peaceful. He said Saudi Arabia has not produced video or photographic evidence of violence committed at the time.

But Saudi authorities have frequently characterized anti-government demonstrations in the country’s Eastern Province as violent, saying that demonstrators attacked both security forces and civilians.