Belgium's Constitutional Court on Wednesday started its final hearing on an extradition treaty with Iran that would allow the transfer of Assadollah Assadi, an Iranian diplomat who is accused of masterminding a bomb plot in Paris in 2018. But the treaty would also allow the release of Belgian aid worker Olivier Vandecasteele, whom Iran's authorities sentenced to 28 years in jail on spying charges.
It is the last chance for Vandecasteele's lawyers to persuade the court to reinstate an extradition treaty with Tehran that may send him back home.
On 8 December, opponents led by the National Council of Resistance of Iran (NCRI), a coalition of Iranian dissidents in exile, managed to convince Belgian judicial authorities to suspend the treaty, which had been ratified in July following Vandecasteele's detention.
They argued that the treaty would also allow the return to Iran of Assadi, an Iranian diplomat who is accused of masterminding a thwarted plot to bomb a NCRI gathering in Paris in 2018.
During that gathering, which drew some 25,000 people in the Villepinte convention centre just outside the French capital, police arrested a Belgian-Iranian couple carrying explosives, which investigators say were intended to be used to attack the NCRI gathering.
Assadi, who worked at Iran's embassy in Austria, was found guilty of masterminding the plot and sentenced to 20 years by a Belgian court in February 2021.
Foreign nationals arrested
Months later, Vandecasteele – who had lived in Iran since 2015, working first as country director for the Norwegian Refugee Council and then for Relief International – returned from Belgium to Iran and was detained by its security services.
He became one of several foreign citizens held in Tehran's jails – accused of vague crimes and, according to their advocates, unfairly tried.
In July, the Belgian government argued that an extradition treaty was the only route possible to free Vandecasteele.
But the Belgian opposition immediately said that the agreement with Tehran was "tailor-made" to permit Assadi's release. NCRI exiles also mounted street protests and a vigorous lobbying campaign.
In early October the NCRI, together with its leader, Maryam Rajavi, and nine other signatories, asked the Belgian Constitutional Court to nullify the prisoner exchange treaty.
Vandecasteele's lawyers, along with the Belgian government, argued against the suspension.
Legal wrangle
A court document published on 8 December, which presented the arguments of both sides, states that Vandecasteele had been "arbitrarily detained since 24 February 2022 in Iranian jails under bad circumstances".
It also noted an "improvement" in his situation after the treaty between Belgium and Iran was initially approved, just weeks after his imprisonment.
But the NCRI argued that if the treaty came into force it was "very likely" that Assadi would then be transferred to Iran and "he would never serve his full prison sentence".
Moreover, NCRI's lawyers argued that its members' lives would be in serious danger because Assadi "would be able to continue his terrorist activities, aimed at eliminating all opponents of the Iranian regime".
On 14 December, a week after the court suspended the treaty, Iran sentenced Vandecasteele to 28 years in prison. Another 12 years, as well as a whipping, were added to his sentence in January.
The court has until 8 March – exactly three months after it suspended the treaty – to overturn that decision, which would then pave the way for both Vandecasteele and Assadi to return home.
