Police arrested Abdi Aziz Mahamud, a 26-year-old Somali citizen living in Sweden, and Swedish citizens Salar Sami Mahamood, 24, and Abdi Weli Mohamud, 26, in September 2011, after finding the men carrying weapons outside an art exhibition Vilks planned to attend.
The appeals court in Gothenburg ruled that while the suspects' actions that night were suspicious there was no concrete evidence that they intended to kill Vilks, the Swedish News Agency TT reported Monday.
Vilks has been the target of death threats since 2007 when a newspaper published his cartoon depicting the Prophet Muhammad as a dog.
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