A teenager was kept captive by a couple for eight years and forced to pull a horse cart.
The 19-year-old German girl was rescued after suffering years of starvation and abuse at the hands of a Bosnian man and woman, according to news reports.
She has been named by local media as Bettina Siegner.
The terrified teen was taken to safety and the couple, Milenko Marinkovic, 52, and his wife Slavojka, 45, have been detained on suspicion of treating the woman in an inhuman way, "forbidding her any contacts with people, forbidding her to attend school."
Local media reported that the girl had arrived in Bosnia from Germany eight years ago with her mother, who could have entered into a sham marriage with Milenko Marinkovic to allow him to obtain a German residency permit.
The mother still lives in the northeastern village of Kalesija, Bosnia, where the girl had been held since 2004.
Damir Arnautovic, a spokesman for the prosecution in Tuzla, told Reuters the teenager had been in a bad physical and psychological state and had no papers.
Arnautovic said the mother had been interrogated by the police as a witness and her role was being investigated.
A neighbour had tipped off the police and said the woman had been forced into hard labour and was covered in bruises and scars.
Sead Makalic, 53, said he once witnessed Marinkovic harness the girl to a horse cart and forced her to pull it with him and his friend sitting in it while he whipped her.
"I could not watch them beat and starve her any more," he said.
Another villager claimed the girl had been forced to eat pig feed and sleep with pigs.