Four out of six kids. From a single foster care home. Four of them, lured into prostitution. Naïve me, but I was shocked.

It seemed beyond my imagination that four girls, supposedly in school, could instead be detoured into the grasp of Homestead pimps, for months, without anyone noticing. Kids, our kids, wards of our state government, spent their school days turning $100 tricks.

When a child advocate told the Herald’s Carol Marbin Miller last week that the case demonstrated an “extreme lack of supervision of these girls,” it seemed beyond understatement. But when I contacted experts in sex trafficking Monday, nobody was much shocked. They said foster kids often suffer the characteristics that make them vulnerable to exploitation.

Jill Levenson of Lynn University, an expert in sex crimes and a former child protection social worker, spoke of how often foster kids come from brutal family situations, from drugged out parents or child sexual abuse. Needy, troubled, difficult kids, with low self esteem. Desperate for attention. Wanting someone to take care of them. Then comes the pimps, showering them with attention. “Making them feel really special,” Levenson said.

Joan Reid of the Department of Rehabilitation and Mental Health Counseling at the University of South Florida said much the same thing, via email. And added, chillingly, “Girls in foster care are endangered due to the increased demand of buyers of sex [johns] for fresh, younger looking girls.”

After a similar case in Chicago in 2008, group homes were dubbed “magnets for pimps.” You’d think, given the vulnerabilities of their clients, that operators of foster homes would be particularly vigilant. Nola Brantley, founder and director of a California-based operation dedicated to rescuing children caught up in prostitution, talked about the stunning lack of awareness she has discovered among foster care providers.

Another theme emerging from the interviews echoed the problem Miami-Dade State Attorney Katherine Fernández Rundle discussed last week after the foster kid pimp ring was busted. Investigators must first break that strange, confounding bond the girls maintain with their pimps, often refusing to testify against the men who’ve beaten them, prostituted them and taken most of the money they earned.

This case had another familiar characteristic. One of the four girls in the Miami-Dade group home had recruited the others. Joan Reid warned that, “A pimp/trafficker will often use ‘his girls’ to recruit new girls, so placing previously trafficked girls, who have not had time to heal and psychologically recover, into group homes with other children puts the other children at risk.”

The Florida Legislature passed a law last spring that would do just that, create separate “safe harbors” for sexually exploited children, with training for police, with special treatment and facilities for kids who were once simply flung into the criminal justice system.

The new law goes into effect Jan. ,1 but with a caveat all too familiar to Florida’s child advocates. “To the extent funds are available.”