GOP presidential candidate Donald Trump said Wednesday there are secret papers that show Saudi Arabia was behind the World Trade Center attack on 9/11.Trump has been hitting rival Jeb Bush over his how his brother, former President George W. Bush, responded to the 9/11 attacks, but at a Wednesday campaign event in Bluffton, South Carolina, he mentioned that the Saudis might have been involved,"It wasn't the Iraqis that knocked down the World Trade Center," Trump said, noting that the Bush administration still invaded Iraq after the attack."We went after Iraq, we decimated the country, Iran’s taking over," he said. "But it wasn’t the Iraqis. You will find out who really knocked down the World Trade Center, 'cause they have papers in there that are very secret, you may find it's the Saudis, OK? But you will find out."While 15 of the 19 terrorists who carried out the 9/11 attacks were Saudi nationals, as was the mastermind Osama bin Laden, no public evidence has shown the Saudi government was involved.