They were wounded in war and now cannot fight to defend our country overseas. But wounded U.S. vets have taken on a new purpose and started to fight the domestic war on child predators, who, just like most modern terrorists, hide in the shadows and strike when no one is looking, according to a report on ABC News.

This is a war that has been raging on for as long as time can count, but only now has it been expanded due to the onslaught of the digital age and the expanded access to young children that predators now have. But the war to fight them has turned their digital security against themselves.

Wounded U.S. Marine Sgt. Justin Gaertner lost his legs while fighting in Afghanistan in 2010. He now uses artificial limbs to maneuver around daily and is assisted by a service dog. But that does not mean he is not protecting anyone.

Gaertner signed up for a pilot program that was rolled out by the Department of Homeland Security named HERO Corps, which stands for Human Exploitation Rescue Operations Corps. This program trains wounded vets to use computer and information technology to corner child predators and put them behind bars.

Although the program took a lot of getting used, Gaertner told ABC News that his new job puts child predators behind bars and gives him a strong sense of pride and accomplishment.

"It's never ending ... [the] despicable things that people are doing to children," Gaertner told ABC News.

According to the report, Gaertner is a 2013 graduate of the training program and has been with it ever since. The program was actually created by Immigration and Customs Enforcement (I.C.E.), which is a division of D.H.S.

The program thus far has been successful enough that the HERO Act was signed into law this year and now, wounded U.S. veterans have a chance to return to the battlefield and fulfill a new role that comes with a sense of pride. This is a lasting legacy for these warriors that could potentially be passed on for perpetual generations to come.

Gaertner was part of the team that helped take down the 40-year-old Florida man Benjamin Cuadrado, who has been sentenced to 80 years in prison for producing 70 videos of him having sex with children 2 years of age and younger.