From crisisgroup.org

Those escaping violence at home are targeted again as they flee. Ideal victims, many have relatives who can be stung for ransom payments; lacking legal status, they are less likely than locals to report serious crimes like assault, extortion or kidnapping. They are also vulnerable to trafficking: the sex industry along the Mexican/Guatemalan border is largely driven by supply of migrants, especially adolescents, some of whom are held in virtual debt bondage to traffickers. A recent study, estimating that for every reported case there were 30 hidden victims, put sexually-exploited victims in Guatemala alone at nearly 50,000.