CHICAGO (CBS) — Although numbers are vague, the crime of human trafficking presents a real challenge to law enforcement and welfare agencies, who have teamed up to try to raise awareness of troubled children who end up being manipulated or forced into prostitution.

WBBM Newsradio’s John Cody reports, in two years, the Cook County Sheriff’s Department has rounded up 300 runaways from group homes, many of whom had been coerced into prostitution.

“The notion that somehow – whether you’re talking about a child or a woman – it’s a voluntary act, that they’re having this guy who’s taking 100 percent of the money, occasionally beats you, fills you up with heroin and the like … that somehow this is a chosen profession is insane,” Sheriff Tom Dart said.

The sheriff joined Cook County prosecutors, the FBI, officials from the Illinois Department of Children and Family Services, and other agencies to launch a public awareness campaign called “Our Children Are Not For Sale.”

Sex trafficking has made international headlines in recent weeks, in the wake of the kidnapping of 276 Nigerian school girls by a terrorist group which has vowed to sell the girls into slavery. Dart and his colleagues said it’s not a problem that hits close to home, too.

Cook County State’s Attorney Anita Alvarez said the problem here is already troubled teens who flee group homes and end up in the clutches of pimps.

“Do you see a young girl who’s always with someone who’s 30 years older than her walking the streets? If there’s a home, apartment in your neighborhood where there’s all kinds of traffic coming in and out, that can alert neighbors that there might be something going on,” she said.

FBI Assistant Special Agent-in-Charge Ricardo Pagan, who runs the bureau’s Violent Crimes Against Children Task Force in Chicago, said human trafficking – or forced prostitution – is a low-visibility crime, but one that’s widespread and serious.

“Last year at the Super Bowl, we recovered 106 commercially-exploited children, and we arrested approximately 150, 151 pimps,” he said.

Officials said those who think they know of minors being pimped out by adults should call 911 or contact the Illinois Department of Children and Family Services and let them know what’s going on.