John Nixon, who questioned Saddam Hussein after he was found hiding in a cave in December 2003, said the Iraqi dictator’s death warrant was signed after the 9/11 attacks.
Discussing the first days of the Bush administration on BBC Radio 4’s Today Programme, Mr Nixon said: “We had gotten word that they saw Iraq as ‘unfinished business’.
“We never really understood at that point what unfinished business meant, but we knew that they wanted to do something.”
He added, “You know, they had their minds made up from day one. And then after 9/11, that’s when the death warrant for Saddam Hussein was signed.”
The CIA interrogator has previously said it quickly became clear Mr Hussein had not developed weapons of mass destruction when he questioned him.
He has also spoken out against the Iraq war numerous times, saying America was critically mistaken about the intervention in a number of ways.