The US Department of Justice is preparing to file historic criminal charges against former Cuban president Raúl Castro for the 1996 shootdown of two humanitarian aircraft.Prosecutors possess audio recordings which allegedly capture the former defense minister ordering the destruction of the planes operated by Brothers to the Rescue.The attack killed four people, including three US citizens, over international waters near the Cuban coast.This legal move follows an ongoing petroleum blockade and mounting pressure from the US government to force a transition in the island's political leadership.