New details were released Sunday on the joint Mexico-U.S. effort to capture one of the world's most wanted drug lords.

Joaquin "El Chapo" Guzman, the head of the Sinaloa cartel, was arrested Saturday in the resort city of Mazatlan, Mexico.

According to a U.S. government official, cellphone intercepts, and the arrests of Guzman's courier and top aide were what helped bring him to justice.

A wire tap run by Immigration and Customs Enforcement officials lead authorities to a beach-front condo where Guzman was found armed with a military-style assault rifle.

Guzman ran the international Sinaloa cartel, Guzman's $3 billion-a-year drug smuggling empire, which is blamed for 25 percent of illegal drugs entering the U.S. It is an empire that thrives on using boats, planes, tunnels and even submarines to move tons of contraband.

"He's really the godfather, if you will, of the cartels that has brought -- smuggled so many drugs into the United States, killed so many people in Mexico and around the world, and to bring him to justice, finally, after so many decades, is a great victory," said Rep. Michael McCaul, chairman of the House Homeland Security Committee.

Guzman is being held in a maximum security prison. U.S. authorities are encouraging Mexican officials to extradite the drug kingpin to ensure he won't escape, something he has done before.

Guzman faces at least seven federal indictments.