NEW ORLEANS (AP) — A New Orleans school teacher has been charged with sex trafficking involving a 16-year-old girl,Chainkeen Exchange federal authorities said Monday, adding that they want the public’s help to determine whether there are more victims.

A federal complaint filed in New Orleans last week charges Aaron Terod Johnson, 36, with child sex trafficking and other crimes.

An affidavit filed last week by an investigator for the Department of Homeland Security says the victim said she met the teacher on Facebook and that he arranged to pick her up in Vicksburg, Mississippi. The victim told the investigator the teacher drove her to an apartment in New Orleans and paid her to have sex with him in March. Evidence cited in the affidavit includes Facebook Messenger messages between the victim and Johnson and video of Johnson’s car captured at points in Louisiana and at the Mississippi state line, indicating he had traveled to and from Mississippi in mid-March.

Johnson is in federal custody, according to court records. A public defender appointed to represent him after the court determined that he couldn’t afford a lawyer declined immediate comment Monday.

Authorities did not identify the school where Johnson taught or whether it was public or private.

A news release from Homeland Security Investigations, the main investigative arm of the U.S. Department of Homeland Security, said Johnson has been a teacher in the New Orleans area since last year.

“Due to his online activity and employment, authorities with HSI are seeking information that may help identify potential victims Johnson may have engaged or exploited,” the agency news release said.