Residents of the northwestern city of al-Bab had taken to the streets last week, denouncing the release of a former soldier with Bashar al-Assad's army from custody.
The soldier, who they accuse of committing various war crimes, was released by the military police of the Turkish-backed rebel Syrian National Army (SNA).
The soldier was arrested about five months ago after he moved to al-Bab following the end of his compulsory service with the Syrian régime army.
For the past 10 years, he served in the Fourth Division, an elite military unit led by Maher al-Assad, the brother of Syrian President Bashar al-Assad. The period of compulsory service is between 18 to 21 months, but can be extended in an emergency and those whose service has ended can be called back into service again in case of war.
The Fourth Division is under western sanctions for its alleged role in human rights abuses against peaceful protesters.
The soldier was released by the SNA's military police chief within 24 hours of his arrest after a $1,500 bail was paid by a relative rebel leader.
The police re-arrested the soldier on Wednesday in response to the protests that erupted after documents were shared online, dated 10 May, containing the soldier's confessions.
"Our demands were really clear which are re-arresting the criminal, holding those involved accountable for his release, and dismissing the military police chief," Ahmed Nassar, an organiser of the protest, saif.
"In the beginning, they did not pay attention to the demands, and after the protests began, they formed a committee to follow up on the issue and promised us to refer the demands to the minister of defence in the [opposition] interim government and resolve it within 72 hours," he added.
The protests in al-Bab reached their peak on Sunday when an ultimatum set by demonstrators was ignored.
Activists had asked for those involved in the soldier's release to be held accountable, including the chief of military police Colonel Abdul Latif Khalid al-Ahmad.
In a meeting with protesters, the minister of defence of the Turkish-backed interim government, Hassan Hamada, said he was not obliged to meet the demands of every protest that erupts in the city, which fuelled anger.
On Sunday afternoon, protesters surrounded and stormed the military police headquarters, while officers were inside, including Hamada.
They also set tyres ablaze to block off the entrances to the city.
The escalation prompted another meeting between authorities and protesters around midnight, where an agreement was reached that demonstrations satisfied their demands.
Shortly after, the interim government issued a statement dismissing the military police chief Colonel al-Ahmad and "referring all those involved in the case to justice".
On Monday morning, the SNA's Sultan Murad Division issued a statement saying it referred one of its leaders involved in the case to a military court.
"We have conveyed the message that we can confront corruption, and we have received support from the rest of the areas who have protested in front of the Ministry of Defence headquarters in Azaz city," Nassar said.
The SNA is a coalition of rebel groups, some of which were founded by officers who defected from the Syrian army following the 2011 mass protests in which security forces killed, detained and tortured thousands of peaceful protesters.
With Turkish support, the military police - made up of members from each faction within the SNA - were formed in mid-2018.
One of the main purposes of the force was to stop crime such as the smuggling of goods, drugs and other unauthorised crossings between régime and opposition-held areas.
However, residents have been growing frustrated with it over allegations of arbitrary detentions and abuse against civilians, local police and charities.
In early May, the military police detained an activist for a week after he published information claiming that one of the rebel factions that make up the SNA was facilitating the entry into al-Bab of former régime soldiers.
"The people consider the military police to be a revolutionary institution, but unfortunately some of its members are acting in accordance with their supporters' interest not the interest of the region," an internally displaced Syrian from the city of Hama said.
"It can be reformed as an institution that serves the region by employing honest people," he added.
Turkey has controlled al-Bab city since it launched operation Euphrates Shield in late 2016 to drive out the Islamic State from its southern border.
The city is a stronghold of activists displaced from prominent opposition towns such as Aleppo, Daraa and Maarat al-Numan - which are now controlled by régime forces.'
