The bodies of the two men, aged 21 and 39, were found in a road through a forest near Surte. They had both been shot with an AK4 automatic weapon.
The older man had come to recover his Mercedes, which had been stolen by a criminal gang in Örebro, from the 24-year-old. He had taken 40,000 kronor in cash to the meeting, and the 21-year-old had joined him to keep him company.
The older victim filmed the journey to the meeting with his mobile phone, a film which later proved vital to police.
The convicted man has been given a full psychiatric examination, which showed that he was not suffering from serious mental problems, either now or at the time of the killings.
The man, a Tunisian citizen, was told by the Court of Appeal in Gothenburg that he would be deported from Sweden upon his release.
A 21-year-old man previously had his conviction for harbouring a known criminal, and his two year prison sentence, upheld on appeal. A 38-year-old man was sentenced to eight months imprisonment for the same offence.