Ex-gang member confronts past

In the late 1990s, Derek "Shotgun" Brown controlled these streets in Chicago as a chief in the notorious Vice Lords street gang. Today, he's back on those streets, but for another reason: to stop the cycle of violence he had once fueled.

After years in prison, Brown founded the North Lawndale Boxing League to help keep kids off the streets after school and avoid making the same mistakes that he did. But in the years since Brown's time with the gang, the Vice Lords gang has grown into one of the largest in the area.

"It's a big virus over here, a real plague," he said to America Tonight correspondent Christof Putzel. That "plague" has left Brown with some deep regrets. "I wake up everyday with that on my mind," he told Putzel. "It just shames me."

Putzel spent months in Chicago for a four-part series on the city's gang violence, and the people working to end it. Brown was his entree into the Chicago underworld.

"I’ve covered stories in war zones and places where people were desperate for food and life itself," Putzel said, "but I never felt the same level of intensity on the streets as I did when I started reporting on the south and west sides of Chicago."