Mike Tyson\'s travel visa has been revoked in New Zealand because the former U.S. boxing champ is a convicted rapist, immigration officials said. Tyson served three years of a six-year prison sentence for raping an 18-year-old woman in 1992. He planned to bring his one-man show, which previously had limited runs in Las Vegas and on Broadway, to New Zealand next month. Although he was initially granted a visa, it was later rescinded when it was discovered one of the criteria necessary for its approval wasn\'t met, The New Zealand Herald reported. The Auckland newspaper said a letter of support believed to have been issued by the Life Education Trust charity was a significant factor in acceptance of the application and the visa was revoked after officials learned a volunteer with the trust, who had no authorization to do so, penned the letter. The Herald quoted New Zealand Prime Minister John Key as saying he backed the decision to revoke Tyson\'s visa. \"I think [Associate Immigration Minister Kate Wilkinson] made the right decision on the basis of the fact that the Life Education Trust has withdrawn their support,\" Key said. \"I find the concept of rape abhorrent -- it\'s wrong and I think we need to take that very, very seriously -- but I accept the view that we take these things on a case by case basis and it was a long time ago,\" Key said. \"I think she took the view -- and it was a very finely balanced call -- that if he was going to talk to people he might be able to use his life story to change behavior in any people who might be wanting to turn their lives around. But the reality is that the Life Education Trust came to us, had a change of heart and withdrew their support, so she really had no option but to withdraw the nomination.\"