After 25 years of being an FBI agent, Joe Navarro certainly knows something about lies, tricks to deceive and body language. Recently, Mr. Navarro decided to apply some of his knowledge to help poker players identify whether an opponent has a good hand or is just bluffing.

Currently, Mr. Navarro along with poker star Annie Duke teaches body language reading techniques at the poker training camp managed by Phil Hellmuth. “Reading people is paramount to success,” Mr. Navarro explained. “I treat them just like the special agents I train. I've spent the last 15 years working in the behavioral analysis program, which is designed to study the behavior of spies and terrorists.”

Navarro, 54, first realized he had skills for poker a few years ago while filming a documentary about human body language experts and lie detector machines. Nowadays, hundreds of his former students have signed up for the World Series of Poker event whose winner will receive more than $12 million.

Mr. Navarro teaches that a player who wrinkles his nose has bad cards, interlocking fingers means that something worries the player and when a player leans into the table, he thinks he is going to win the pot.