were fatally shot in the backs of their heads while riding bicycles after unidentified assailants on a motorcycle opened fire in the Pigneto district of the capital where they were staying.

Police say at least six bullets were fired. Gun violence is extremely rare in Italy, even in cases involving organized crime, where strict gun laws make it difficult to own or carry firearms. Police say the motive is likely tied to the so-called “war of hangers” among Chinese criminal gangs who specialize in the textile sector, especially fast fashion factories in the Tuscan town of Prato, near Florence, police said at a press conference Tuesday. Zhang, who went by the nickname “Asheng” was on trial along with 78 other people in Florence accused of coordinating illegal criminal operations across Italy, France, Germany and Spain.

He was due to testify in the coming weeks and thought to be the second in command of one of the most powerful gangs that operates in Europe, according to documents tied to the court proceedings. Zhang denied the allegations and CNN reached out to his lawyer for comment. (CNN)