Wichita ? Wichita police say the cases of teenage girls being forced into sexual slavery are increasing in the city.

Police and social workers have investigated four such cases this year and they suspect there are many other young girls at risk. They blame the increase on street gangs, who particularly exploit runaways and homeless children. They believe that 300 to 400 Wichita-area children every year are at risk of becoming victims of sexual exploitation.

Mike Nagy, an officer with the Wichita-Sedgwick County Exploited and Missing Child Unit, says gangs trade and sell children like slaves. But the crimes are hard to investigate because the victims often are brainwashed or threatened, and most won’t testify.

“They need to know that we have no intention of arresting or prosecuting them,” said Kent Bauman, an EMCU officer. “Our purpose when we work these cases is to go after the pimps and gangs who are harming these children.”

The extent of the problem, which began growing worse in the past few years, is more extensive than police had originally thought.

The gangs lure the children with food, money, shelter and romance, police said. Gang members train their victims in sex acts, often using pornographic movies as “training films.”

The victims then are either forced into the local sex trade or trafficked on the Internet or to larger cities, police said.

Social worker Karen Countryman-Roswurm, who has studied the problem and interviewed hundreds of victims, said the pimps can make hundreds of thousands of dollars off a single child.

Street gangs have learned that sex trafficking is safer and more lucrative than dealing in guns or drugs, Bauman said.

The gangs also are making a lot of money from the porn industry, Countryman-Roswurm said. The customers who are creating a demand for child pornography also should be held accountable, she said.

“Every time they buy a pornographic film or pay for sex, they are helping create demand for a crime where children are exploited,” she said.

And while the victims are children from every race and social level, Countryman-Roswurm said, most of the customers come from the same group.

“The people who create the demand and provide the cash for the sex trade are mostly white, middle-aged, middle- or upper-income men,” she said. “We have to stop arresting the victims and arrest instead the buyer and seller.”

Nagy said most of the local victims are drawn from runaways who “couch surf” from house to house looking for a place to stay, or are homeless and live on the local streets. Because of that, they are easy targets, he said.

“A guy drives up beside you and asks if you need a place to stay,” Nagy said. “They offer money, they buy them food and clothes, and these kids are feeling hungry and vulnerable.”

Some of the pimps offer friendship or even romance that draws young victims in.

“The girls involved think the guy wants to be her boyfriend,” said Anne Lund, a social worker investigator with the EMCU.

The girls think they’re in love, but to the pimps, it’s just business.

“It is really tough to talk some of these girls out of it,” Lund said.

Police say they have frequent contact with runaways who seem defiant about their parents, but have no idea about what they’ll face on the streets.

“A lot of these runaway children know what they are running away from,” Nagy said, “but most of them have no idea what they are running to.”

Social workers and law enforcement officers will gather today at a conference titled “Community Action to End Domestic Sexual Exploitation” to coordinate a stronger response to the problem.