(CNN)The horse patrol incident in Del Rio, Texas, that drew swift condemnation from senior Biden administration officials will not be investigated by the Department of Homeland Security's inspector general, the department announced Tuesday. US Customs and Border Protection had referred the incident -- where Border Patrol agents on horseback aggressively confronted migrants -- to the watchdog, according to the Department of Homeland Security. Instead, CBP's Office of Professional Responsibility is now investigating the incident, the department said, adding that the office has reviewed videos and photographs and interviewed witnesses, employees and CBP leadership....