Border agents seen in controversial photos on horseback not yet questioned: Source

The U.S. Border Patrol agents at the center of controversy involving their use of horses to block Haitian migrants from entering the U.S. have not yet been questioned.

The U.S. Border Patrol agents at the center of a controversy stemming from their use of horses to block Haitian migrants from entering the U.S. have not yet been questioned more than a month after the incident took place, according to a law enforcement official.

Images of mounted patrol agents using their horses to push back migrants, mostly Haitian, stirred national controversy as an unprecedented number attempted to cross the Rio Grande into the small border town of Del Rio, Texas, in September. The Department of Homeland Security launched an internal investigation into the matter shortly after the images came out.

Homeland Security Secretary Alejandro Mayorkas promised a swift investigation into the horse patrol over a month ago, assuring lawmakers it would yield findings days later. As of publication, and despite multiple requests for comment from ABC News, the administration has not publicly announced any findings.

Preliminary findings from Customs and Border Protection's Office of Professional Responsibility have been handed over to the Justice Department to determine if criminal charges are warranted, according to two officials who were not authorized to speak publicly.