Leftist opposition leader’s assassination caused turmoil in wake of 2011 uprising that brought down President Ben Ali.

A court in Tunisia has sentenced four people to death and two to life imprisonment for their role in the assassination of opposition leader Chokri Belaid 11 years ago.

The sentences were confirmed on Wednesday by the deputy public prosecutor of the anti-terror judicial division. A total of 23 people had been charged in connection with the murder, with sentences ranging from two to 120 years handed down to other defendants, with five acquitted.

Dozens of Belaid supporters had gathered near the court in Tunis since Tuesday night, raising slogans demanding justice.

They chanted “Chokri is always alive” and “we are loyal to the blood of the martyrs”.

Belaid was shot dead in his car outside his home on February 6, 2013. The secretary-general of the Democratic Patriots Party was a fierce critic of the then-ruling Islamist party Ennahdha, claiming it had turned a blind eye to violence perpetrated against secularists.

His funeral was one of the largest public outpourings of grief in Tunisian history, with an estimated one million people taking to the streets, leading to massive protests.

The assassination triggered one of the biggest political crises Tunisia had experienced in the wake of the 2011 uprising that brought down President Zine El Abidine Ben Ali, casting doubt over the independence of the country’s judiciary and security forces.

Months later, a second opposition figure, pan-Arab leftist Mohamed Brahimi, was shot under similar circumstances, the ensuing political pressure forcing the government to step down.

The authorities blamed the killings on Ansar al-Sharia, a Salafist group suspected of links to al-Qaeda that was designated a terror organisation in August 2013.

Belaid’s family and secularist politicians accused Ennahdha party leaders of being behind the assassination when they were leading the government.

Ennahdha strongly denies any connection to the assassination. “The details concluded by the judicial circles clearly show evidence of the innocence” of the Ennahdha, it said on Wednesday in a statement.

It added that the verdict should restore respect to those subject to false political accusations, most notably the leader of Ennahdha, Rached Ghannouchi, recently sentenced to three years in prison amid a government crackdown on the opposition.