Ten Americans held for trying to leave Haiti with 33 children were charged with child kidnapping and criminal association.
The five men and five women, most of them members of two Baptist churches in Idaho, will be dealt with under the Haitian legal system. It was earlier reported that the could face justice in the US.
Rather than have an open trial, an investigative judge will consider the evidence but could take up to three months to reach a verdict, said Edwin Coq, the group's Haitian lawyer.
The charges carry prison sentences of up to 15 years and were announced after prosecutors questioned the Americans during a private meeting in Port-au-Prince.
Mr Coq said a prosecutor had told him the 10 were charged because they had the children in their possession when they were stopped last Friday at the Dominican Republic border.
They were taken back to jail after the hearing. Jean Ferge Joseph, the Haitian deputy prosecutor, told them the investigative judge could either free them or hold them for "further proceedings".
Haitian officials said the Americans had neither the authorisation nor the travel documents, including passports, to take the children out of the country.
Laura Silsby, who led the mission, initially claimed the children all came from an orphanage. However, it has since emerged that many had living parents who gave them up to the Americans on the guarantee they would be given a better life and a decent education.
The case is diplomatically sensitive as Haitians have expressed fears about foreign interference - particularly by America - after the devastating earthquake on January 12.