A Stockholm court on Thursday handed down a life term to Swedish militant Osama Krayem over the 2015 murder of a Jordanian pilot burned alive by the Islamic State group in Syria.
The Swedish court was the first to try a person over the infamous killing which sparked outrage around the world.
Judge Anna Liljenberg Gullesjo said "the investigation has shown that the defendant was at the execution site, uniformed and armed, and allowed himself to be filmed."
Although video evidence showed that another man lit the fire, the judge said the "defendant's actions contributed so significantly to the death of the victim that he should be considered a perpetrator."
Krayem, who is serving long prison sentences for his role in the Paris and Brussels attacks in 2015 and 2016, was given a life sentence for "serious war crimes and terrorist crimes"
On 24 December 2014, an aircraft belonging to the Royal Jordanian Air Force crashed in Syria.
The pilot, Maaz al-Kassasbeh, was captured the same day by IS fighters near the central city of Raqqa and was burned alive in a cage sometime before 3 February 2015, when a slickly-produced video of the gruesome killing was published, according to the prosecution.
Gullesjo said Krayem's actions consisted of "guarding the victim both before and during the execution and taking him to the cage where he was set alight while still alive."
The court also awarded compensation to the parents and siblings of the Jordanian pilot, amounting to 80,000 Swedish kronor ($8,200) each.
Prosecutors have been unable to determine the exact date of the murder, but the investigation has identified the location.
The 32-year-old militant remained silent throughout the hearings, which lasted between 4 June and 26 June, though segments from interrogations with Krayem conducted during the investigation were read out and played during the trial.
The fact that the defendent did not speak did not "significantly impact the ruling, as the prosecution presented solid evidence, and the investigation was thorough," Gullesjo told AFP.
According to his lawyer, Krayem insisted he had spent only 15 to 20 minutes on-site, unaware of what was going to happen until he saw the cameras.
"This verdict somewhat comforts the family," the pilot's brother Jawdat al-Kassasbeh, who was a civil party to the case, told AFP.
"We thank Sweden and the impartial Swedish judiciary for their efforts in pursuing this case," the brother added.
His lawyer lamented in court that Krayem showed no empathy or remorse for his actions.
"Most people who witnessed what Maaz went through would undoubtedly need lifelong, or at least long-term, treatment to overcome the trauma that this causes in a normal individual," Mikael Westerlund told the court.
The pilot's brother had travelled from Jordan for the trial to testify to the pain, still raw, that he shares with his loved ones.
"Krayem, on the other hand, does not seem to have been traumatised, but inspired. Inspired to continue his terrorist activities, which led him to participate in and then be convicted of terrorist acts in Europe," Westerlund added.
Krayem, who is from Malmo in southern Sweden, was sentenced to 30 years in prison in France for helping plan the November 2015 Paris attacks and to life imprisonment in Belgium for the 2016 attacks at Brussels' main airport and metro station.
On 12 March, France agreed to hand him over to Sweden for nine months, the time needed for the investigation and trial.
He must be returned to France by 27 December at the latest, the Stockholm court said Thursday.