Runaway girls seeking refuge, teenagers responding to online flattery and students accepting a classmate's offer to make money are finding themselves victims of the same fate: being lured into child prostitution.

Child sex trafficking is a growing threat in the D.C. region because gangs are increasingly getting into the business and pimps' use of online tools has made it easier to recruit and sell teenage girls, according to local law enforcement officials.

Many recent cases in the area have involved gangs: In March, five Fairfax County-based members of the Crips gang were charged with prostituting area high school students; two pleaded guilty last week. Members of MS-13 and other gangs have faced charges for trafficking runaway girls.

Reporting trafficking
If you are a victim or want to report a suspected trafficking situation, call the National Human Trafficking Resource Center at 888-373-7888.

Gangs are moving from trading drugs and weapons to trafficking prostitutes to make money, said Neil MacBride, the U.S. attorney for the Eastern District of Virginia. There are few startup costs associated with sex trafficking, he said, and the gangs don't have to worry about how to transport other contraband.

"It's less risky to traffic humans than drugs," said Elizabeth Scaife, a program associate with Shared Hope International, an anti-sex-trafficking nonprofit.

The gang members, she said, can stay in the background, while the girls shoulder the risk of getting caught. And a child being trafficked is less likely to be detected than drugs.

"I can't sniff out a girl that's been abducted," said Nathan Wilson, founder of the Project Meridian Foundation, an Arlington-based organization that works to fight human trafficking.

Such cases reflect an overall rise in reports of human trafficking. That increase is due to a combination of more cases and better reporting, law enforcement officials and advocacy organizations say.

Calls to the National Human Trafficking Resource Center's hotline from the District, Maryland and Virginia more than doubled between 2009 and 2011.

In the 2010 fiscal year, federal prosecutors nationwide charged 181 people in human-trafficking cases, the "largest number of federal human trafficking prosecutions initiated in a single year," according to the State Department's most recent "Trafficking in Persons" report.

In the Washington region, there's a high number of populations vulnerable to exploitation by traffickers, experts say. Those groups include immigrants and their children, fatherless children, and children in foster care.

And the Internet has made it easier than ever to recruit and sell those children.

Prostitution is no longer confined to street corners, U.S. Attorney for Maryland Rod Rosenstein said. Predators can solicit both victims and customers online.

The Internet "exposes kids to things they wouldn't have seen, puts them in contact with people they wouldn't have contacted," Rosenstein said.

The information teens share on their social networking profiles lets traffickers search for victims by area and age, Scaife said. Online advertisement sites, in turn, are fertile ground for traffickers to find customers.

U.S. Rep. Frank Wolf said that's why he's called for the Justice Department to move to shut down, which is known for hosting ads for child prostitution services. Not shutting down such sites helps traffickers, Wolf said.

"If you have a convenient place that people can go, where the pimp can go, you make it easier," he said.