As the celebratory chants of “U-S-A! U-S-A!” die down, one American’s reaction to Osama Bin Laden’s death is causing an uproar. Pittsburgh Steelers running back Rashard Mendenhall tweeted, “What kind of person celebrates death? It’s amazing how people can HATE a man they have never even heard speak. We’ve only heard one side. ” And for good measure, he added a 9/11Truther-tinged tweet: “We’ll never know what really happened. I just have a hard time believing a plane could take a skyscraper down demolition style.” Steelers president Art Rooney says he can’t explain or comprehend what Mendenhall meant, but that the team is “very proud” of what American troops accomplished. This isn’t the first time Mendenhall has generated controversy on Twitter. In March he expressed support for Minnesota Vikings running back Adrian Peterson when he compared the NFL to modern-day slavery.