On October 18th 2015 (over a year ago), a satirical/fake news site "World News Daily Report" published a fake news story about Donald Trump, saying:
RICHMOND, VA | Donald Trump, the GOP’s 2016 front-runner, brought his campaign to Henrico County on Wednesday night, where he made an unexpected statement after answering a series of questions from the crowd.
Pressed on the subject of the September 11, 2001 terrorist attacks and what he would do to prevent such a thing from happening again, the presidential candidate known for his brash answers completely took his supporters by surprise.
“First of all, the original 9/11 investigation is a total mess and has to be reopened” he told the crowd of supporters. “How do two planes take out three buildings in the same day? I never got my head around the fact that nothing is mentioned about the destruction of Building 7 in the 585 page document” he explained, talking about World Trade Center 7 which also collapsed during the September 11 attacks.
This story appears to be almost entirely fake. Trump did give a rally speech in Richmond, Henrico County, on Oct 14th 2015. However the speech makes no mention of 9/11 and Trump does not answer questions from the crowd.
The "World News Daily Report" is also obviously fake, even stating:
The site also has numerous ludicrous clickbait stories.WNDR assumes however all responsibility for the satirical nature of its articles and for the fictional nature of their content. All characters appearing in the articles in this website – even those based on real people – are entirely fictional and any resemblance between them and any persons, living, dead, or undead is purely a miracle.
Unfortunately the story was regurgitated by the lower end of online media. First reappearing today (November 11th, 2016) on "Your News Wire" a clickbait site that focusses on Conspiracy Theories. They simply cut and paste the WNDR fake story, and added a few paragraphs.
Then it was was repeated by the UK's "Daily Star" tabloid site, and widely repeated by hopeful 9/11 conspiracy theorists on social media.