Phoenix Police Sgt. Steve Martos said the FBI first contacted the local Home Invasion Kidnapping Enforcement unit following a report that three teenage girls had been kidnapped in El Salvador.
The suspects were trying to extort money from the teenage girls' parents and had threatened to sexually assault them if their demands were not met, Martos said.
Authorities entered the house at 6 p.m. Thursday and found 11 minors, the youngest of whom was a 2-year-old girl, as well as the three girls ages 12, 14 and 15.
Investigators believe they had actually been smuggled into the United States, not kidnapped, along with eight other children from Mexico, El Salvador and Colombia, Martos said.
Detectives found one male suspect in the south Phoenix house, who told them he had also been smuggled into the U.S. but could not pay so was put to work "guarding" the others, Martos said.
Police detained two others, a man and a woman, who were driving away from the house as they arrived.
Police said they were working to reunite the children with their families.