But a year later, the military police officer returned to his job as a civilian police officer with the Northglenn, Colo., Police Department with grim scenes of burning oil fields and charred bodies stuck in his mind. Old haunts, familiar streets and routine police work were distorted by the memories of war. He had nightmares, anxiety and flashbacks. He un-holstered his gun during routine traffic stops. One night, while sitting in his cruiser in a parking lot and completing paperwork, he heard a noise behind him.

"I opened the door, rolled out on my stomach and took my gun out," Rankin said. "It was a just a kid walking across the parking lot."

The department's psychologist diagnosed him with Post Traumatic Stress Disorder. Rankin didn't believe it. His symptoms had to be a reaction to the toxin gases he was exposed to during his tour.

"I just chalked it all up -- the nightmares, the flashbacks, my over-reactions -- to the change, because you never come back the same," he said.