Donald Trump famously says there were NJ Muslims celebrating the 9/11 attack on the World Trade Center. The Washington Post's so-called "fact checker" Glenn Kessler reported finding no support for this assertion and awarded Trump four Pinocchios, denoting a maximum lie.
Meanwhile John Hinderaker at Power Line did a quick search and found Kessler's own WaPo had published a report sourced to the Jersey police concerning such celebration. Now Mark Steyn has found the story was covered by The New York Times and a couple of Jersey TV stations too.
Chances are Trump exaggerated some when he said "thousands" were involved, so what? Trump always exaggerates, it is his stock in trade, so sue him.
It seems clear there were some number of radicalized Muslim Arabs in New Jersey who publically expressed joy about the World Trade Center attack. Deal with it!