Members from the National Transportation Safety Board (NTSB) were in Rockingham Monday following up on a deadly bus crash that left four people dead and dozens hurt on the U.S. 74 bypass. The NTSB was looking at the bus’s tire. Officials with the North Carolina Highway Patrol believe a blowout caused the bus to crash, but the investigation remains open. First responders described the scene as "chaotic" and were still having trouble shaking the images of the wreck. “It tears us up on the inside. It’s something that you never forget, these types of incidents - you don’t forget about the rest of your career,” said Hamlet Fire Chief Calvin White. White has been a first responder for almost 40 years and said Saturday’s crash is one he will never forget.