Mexico City (CNN) Honduran President Juan Orlando Hernandez confirms he was investigated by the US Drug Enforcement Administration, according to a statement released by his government on Thursday.

The Honduran statement came two days after the Southern District of New York released an 11-page document, dated 2015, which revealed several people were under investigation, including the Honduran President and his sister, who is now deceased, in an alleged involvement in "large-scale drug-trafficking and money laundering activities relating to the importation of cocaine into the United States."

The investigation began in 2013. It is not clear whether it is still open.

Parts of the prosecution's case have been redacted but many of the details were obtained through conversations with a witness cooperating in the case, the documents say. Known as CW-1, the witness is working with authorities in exchange for "leniency at sentencing."

The filed documents were presented as part of the pretrial motions in the case of President Hernandez's brother, Antonio Hernandez Alvarado.