A midair collision between an Army helicopter and a jetliner killed all 67 people aboard the two aircraft, officials said Thursday, as they scrutinized the actions of the military pilot in the country’s deadliest aviation disaster in almost a quarter century.

Ten people were killed on Tuesday (April 23) after two helicopters collided in mid-air during a rehearsal for a Royal Malaysian Navy (TLDM) parade, the navy said in a statement.