"This case continues to be investigated as a kidnapping for ransom case," the FBI said in a statement.
The man allegedly used an app to create a fake phone number to text the family, according to a federal complaint.
The "Today" show host and her siblings made an emotional plea for the return of their mother, who remains missing in Arizona.
Investigations are continuing after the mother of "Today" show host Savannah Guthrie disappeared over the weekend in what authorities believe was a possible abduction.
Investigators say three men from Brooklyn kidnapped the 18-year-old in Delaware on March 17.
Jean-Dickens Toussaint and his wife, Abigail Toussaint, of Tamarac, Florida, were in Haiti to see ailing relatives and attend a community festival when they were kidnapped while traveling on a bus from Port-au-Prince, their family said.
