Sifting Clues to an Unsmiling Girl

The team is not allowed to send porn but can access new series of images the way college students swap music files, through programs such as Napster and Kazaa. There are thousands to sort through, with new homemade images appearing every day. For hours at a time, Krawczyk looks at pictures of abuse that the average person could not even imagine. His immersion in this sordid world doesn't leave him unaffected.

"Sometimes you just want to take a shower after doing this," Krawczyk says. "Sometimes you want to throw the computer across the room. But when we do get a bad guy, it gives you great satisfaction. He wouldn't have been caught any other way."

Of the unit's 37 arrests last year, 26 resulted from their undercover work.

The banter is tough in the room, with graphic discussions of what they would like to do to the "bad guys" if they could get their hands on them. But it masks an emotional investment in the search and rescue of children who often remind them of their own.

Bulmer, a goateed 16-year veteran with bleached spiky hair, speaks longingly of finding an 11-year-old girl he has tracked since 2002. After extensive analysis of online videos of her, the team has pinpointed her location to a city in the American Northwest and handed the case to the local police.

"Why can't they find her?" he asks. "Give me a plane ticket and I'll go there and find her myself."

Almost every investigator in the office has a talisman to ward off the ghosts that haunt the workday. For Gillespie, it's a Christmas card from the mother of a 3-month-old boy who had been raped by his uncle, thanking Gillespie and encouraging him to keep going even when he wants to give up. Gillespie tells a bit of the child's story, then swivels his chair to face the window when his eyes begin to well up. He turns back, recomposed.

"I look at that sometimes," he says simply. "It makes me feel good."

Krawczyk sometimes sneaks a look at a framed quote from Nietzsche above his computer: "He who fights with monsters should look to it that he himself does not become a monster." But nothing purges the taint of the day like the way his son runs to hug him when he walks through the door at night, he says.