(CNN)Mind games can be stealthy weapons. Perhaps no one knows this better than Eric Maddox.
Today, Maddox is as an independent business consultant. But more than a decade ago, he was the U.S. Army interrogator who used mind games to find the most sought after fugitive of the Iraq War — Saddam Hussein.
In 2003, U.S. forces had invaded Iraq. Saddam was on the run and nowhere to be found. The Army was looking for an interrogator with intelligence experience to join a special team ordered to find the former Iraqi dictator.
Because the Army had trained Maddox as an intelligence linguist and interrogator, he was tapped for the mission. His team detained and questioned Iraqis as it looked for clues about Saddam's whereabouts.
If you think interrogation is about violence or torture, Maddox said, you're wrong. Sometimes it involves negotiations.
"When I'm talking about breaking a prisoner, it has nothing to do with physical contact of any kind," Maddox said.
"It has to do with breaking their previous decision of not cooperating with me to provide me information. And now they choose to provide me that information."
After months of questioning Saddam's ex-bodyguards and their family members, Maddox came face-to-face with an Iraqi who knew where Saddam was.
Maddox persuaded this man to reveal a secret that was heard around the world.
Soon after, the U.S. military raided a farm near Tikrit where Saddam was found hiding in a hole in the ground.
Before his retirement in 2014, Maddox conducted about 2,700 interrogations during his military career. The interrogations people ask about the most — the questioning of detainees leading to the capture of Saddam — are detailed in his book, "Mission: Black List #1."
CNN caught up with Maddox by phone at his home in Oklahoma, where he shared five key interrogation concepts. Some of them, he said, also can apply to negotiations in civilian life:
Identify fears and use them as leverage
What's standing in the way of the person talking? Usually it's fear. Once you identify what the person is afraid of if he or she provides you the information you want, then Maddox says you can create a solution to eliminate those fears.
Then, the person will likely open up.
For example, Maddox says some detainees he interrogated in the field wanted protection for their family members.
"Give them real solutions that I can implement so that when they break, they're not breaking hesitantly, they're breaking pretty strongly," Maddox said. "The guy who gave up Saddam Hussein was breaking hard. When he broke, he was pushing me to do the raid as soon as possible."
Understand the other side's perspective
You may need information for an urgent matter and not have a lot of time. But don't forget that listening with empathy is critically important to the interrogation process, Maddox says.
By putting himself in the shoes of each detainee and listening carefully, he said he found common ground with prisoners and got them to reflect on their friends and their family and their needs.
That information helped him become their problem solvers and to know what to offer detainees during negotiations.
Always give the other side hope
Most likely, the person you're negotiating with isn't being held against their will, like Maddox's detainees. However, the person you're questioning still needs to see that there's a clear way out of the problem you're trying to resolve.
"Complications come when prisoners don't believe you're going to help them," Maddox said.
If they don't think they have a way out, then there's no way they'll want to bargain with you, he said.
Never make friends with the other side
Just because you're lending an empathetic ear and offering a positive perspective doesn't mean you should befriend the person you are trying to extract information from, Maddox notes.
Why not? You'll lose your perspective, and that means you will fail.
Practice the art of deception
During an interrogation or a negotiation, "people are dialed in," Maddox said. "They're watching every single movement and listening to every single word."
An interrogator or a negotiator can use this to their advantage by staging very subtle, deceptive behavior aimed at creating a desired result.
Maddox said this works sometimes in business negotiations, for example.
If you bring several people to your negotiation session, you can use them as part of a strategy.
Do you like the deal that's on the table? If so, you can use deception to prevent further negotiations. Here's how:
At some point, fake a small confrontation among your team members. The other team will mistakenly think your team is unhappy with the deal that's on the table. They'll think that deal is the best deal they can negotiate, and they'll settle for it.
Maddox suggested using other -- more subtle -- deceptive behaviors which could impact the other side — like faking embarrassment or surprise about developments during negotiations.
Now, he provides businesses with lessons on elicitation — which he describes as "how to conduct interviews that gather the truth."
It's a career path that tracks back to war zones in Afghanistan and Iraq, where Maddox learned the skills that made him a master of espionage interrogation.