Where should we try war criminals?

Universal jurisdiction says that crimes like genocide are so heinous that that they can be tried anywhere, no matter where they were committed. Is it right for a country to try a war criminal if they haven’t committed crimes on their soil?

Since the end of the Second World War, more than 15 countries have exercised universal jurisdiction. But opponents argue that it is a breach of each state’s sovereignty and that the process can degenerate into politically-driven show trials. Should any state launch proceedings regardless of the location of the crime and the nationality of the perpetrator or the victim? Is it more significant for war criminals be tried in their own countries or by national and international courts abroad?