Leisa Smith posted a photo of her, the former president and former FLOTUS Laura Bush on March 22 after serving them at the restaurant she works at. The caption read, "Bush did 911 but he did me a solid and left me a (good) tip."
The tweet was retweeted more than 5,000 times before being deleted.
Smith's comment didn't sit well with many people, who took to social media to call the waitress' message inaccurate and insensitive.
"Make sure (and) tell (people) directly affected, (including) wives, kids, moms (and) dads," one social media user wrote of Smith's "super funny joke."
"Bush did not 'do' 9/11, and I agree that is a horrible way to put it," another wrote. "I feel bad for uneducated Americans."
One person even called Smith's comment "pathetic," saying, "Did you post that out of meanness, ignorance or stupidity?"
Smith later posted a response on her Twitter page, saying, "PSA: I don't think Bush actually did 9/11," and claiming it was "just supposed to be a sarcastic joke."
"I have a couple of friends that were the only ones I was expecting to see the tweet," she told Mic. "I was just trying to get a laugh out of my friends, but I in no way actually believe the conspiracy. I actually completely respect Bush and I don't think he actually 'did' 9/11."
The Bushes left Smith a $40 tip on a $21.47 bill. She said they were "the nicest people" she has ever met, that George W. Bush hates mustard and that "his wife doesn't let him drink caffeine."