Rudy Giuliani, whose emotional leadership in the aftermath of the Sept. 11 terror attack defined his term as New York mayor, said that when he learned of Osama bin Laden's death he felt "real satisfaction ... relief [and] ... a sense of revenge."
Giuliani, who spoke to ABC News across the street from the site of the World Trade Center, said there was a time when he wanted to be the one who brought bin Laden to justice.
"I told President Bush once that I wanted to be the one to execute him," Giuliani said. "Revenge is not a noble sentiment, but it is a human one. ... When it [news of bin Laden's death] first happened, I wondered, 'Well, did he just die of natural causes?' That would have been somewhat unsatisfying.
"The fact that the American military caught him and brought him to justice I think will make a lot of people feel better in a way that's almost hard to describe," he said.
Giuliani compared bin Laden's death to Hitler's suicide and cautioned that although bin Laden is gone, al Qaeda's second in command, Ayman al-Zawahiri, will take his place.
"This is like taking out Hitler, or taking out, taking out one of those charismatic leaders for evil. Or maybe Stalin, someone who was an organizing principle for them," Giuliani said. "Zawahiri will replace him, but we'll catch him. It's only a matter of time."
He said Zawahiri doesn't have the charisma or the terrorist credentials that bin Laden had.
"He wasn't the hero of the Afghan war that Bin Laden was. He wasn't the multi-zillionaire that turned into a terrorist," Giuliani said. "He's still very dangerous, I think we can catch him, but it'll help that the major figure who organized this whole effort is now gone."
The former mayor praised the courage of President Obama, the military and intelligence services, but said he'd thought bin Laden would have been caught "a lot sooner."
He said the fact that bin Laden was living in a mansion close to a Pakistani military facility calls into question the loyalty and trustworthiness of some of America's allies.
"I do recognize how difficult it is, you know he's in a part of the world where they're trying to hide him, whether it's Afghanistan, or Pakistan -- look, he was living in a mansion in a suburb of Islamabad," Giuliani said. "Our intelligence ability is terrific. What it says is that we don't really have that many allies in that part of the world as we think. And they undermine us and hate us, and it's something we're going to have to deal with."
The man who became known as America's mayor for his calming presence during and following the worst terrorist attack in American history now warns that America should be prepared for reprisal attacks in the wake of bin Laden's death.
"Long term, this is the great achievement. Long term this is a big defeat for al Qaeda, Islamic extremists, terrorism," Giuliani told ABC News. "But in the short term I think we have to worry about lots of repercussions from this. ... It's probably more dangerous for us."
Giuliani said that when he first heard that Obama was going to address the nation on Sunday night, he initially thought there might have been a terrorist attack that was thwarted.
But when he heard the news of bin Laden's death, he said, it brought back a lot of memories.
To get to the interview with ABC News, held at Trinity Church across the street from Ground Zero, Giuliani drove down the same streets he did on the morning of Sept. 11, 2001.
"I drove down here the same route I drove down here that morning. And there's a lot of mixed feelings," Giuliani said. "I'm satisfied, and I feel relieved that he's caught, but reliving those memories is difficult because you do know it hasn't brought anybody back.
"I mean it's good that he's gone, and this is a big step in defeating terrorism," he said. "But it doesn't really bring anyone back and it doesn't relieve the pain."