Alan Tieger was one of six prosecutors chosen by the US Department of Justice to create and form the ICTY, and was among its first employees, arriving at the Office of the Prosecutor in May 1994, and staying until the end of 1996. In 2001 he returned as Senior Prosecutor, a position he held until the ICTY’s closure in 2017. He has subsequently worked as a prosecutor with the Kosovo Specialist Chambers. He was a trial attorney in Prosecutor v. Tadić, the first case to be tried at the ICTY. As a senior prosecutor at the ICTY, Tieger conducted investigations and prosecutions in the cases of high-profile political and military leaders, including those against Radovan Karadžić, Ratko Mladić, Momčilo Krajišnik and Biljana Plavšić.

"In a case focusing on Radovan Karadžić’s criminal responsibility, the evidence that emerges regarding the participation of other members of the JCE, such as Slobodan Milošević, will inevitably be different than the evidence that would result from a case focusing on a different member of the JCE, and in any event far less than the evidence of criminal responsibility that would arise from a case directly addressing Milošević’s criminal responsibility. For that reason, it would be a mistake to conclude that the Karadžić judgment represents any form of amnesty for Milošević or anyone else."

"Whatever else this judgment might mean for the future, the unprecedented and overwhelming volume of evidence, which was determined by eight international judges from different countries to reveal Karadžić’s criminal responsibility beyond a reasonable doubt, should be a strong bulwark against denial and historical revisionism."