"If you contribute to terrorist organizations, I'm sorry, but you're not welcome in the United States... And that's what happened to Cat Stevens," Robert Bonner, customs and border protection commissioner told United Press International Thursday.
Mystery has surrounded the case of the singer since federal officials diverted a Washington-bound flight he was on to Bangor, Maine, last September. He was deported after being questioned.
Officials said at the time that his name was on a "no fly" list, and that he should not have been allowed to board the plane, but they did not say why.
Stevens, born Steven Georgiou, changed his name to Yusef Islam after becoming a Moslem in the late 1970's.
News reports several years ago linked a Web site and charitable foundation he heads to the Palestinian militant group Hamas, and to the "Blind Sheikh" -- Omar Abdel-Rahman, convicted of involvement in a terrorist plot in New York city a decade ago.
Notable deaths of 2014 [PHOTOS]