If Hizballah was involved, than it is not hard to believe Iran was involved. The problem is: We never heard anything about the investigators asking to interview any Iranian. They were not shy to ask for Syrians to be interviewed and even detained, so why not Iranians? It is unlikely that Iranians will be indicted without even bothering to try and hear their version. Until we read the indictment, I am going to consider these news about Iran's involvement as an interesting conspiracy theory, coming from a place in the world which specializes in conspiracy theories.
Five people killed in car crash near Hebron (Haaretz)