THE HAGUE, Netherlands—A Dutch court convicted a Syrian man Friday of committing a war crime in his country for his role in the 2012 summary execution of a prisoner. The court sentenced the man to 20 years in prison. The case marked the first time a Dutch court has dealt with allegations of war crimes committed in Syria. Dutch law allowed the court in The Hague to take the case because the 49-year-old defendant lives in the Netherlands. He was granted asylum in the Netherlands in 2014. He was convicted in the shooting of a captured Syrian army soldier in Mohassan. The Dutch court said the defendant played a leading role in the shooting and was the first to open fire on the soldier. The court acquitted the man, whose name was not made public, of involvement in a terrorist organization. Dutch prosecutors said during the trial that the army …