A decade after the September 11 attacks, antisemitic conspiracy theories "warping and manipulating" the truth and blaming Israel are still being widely circulated.
The New York-based Anti Defamation League has carried out an in-depth study of the conspiracies that have been discussed over the ten years since American planes were hijacked by terrorists.
In the aftermath of the attacks, fringe conspirators accused shadowy figures in the government or US secret agencies of perpetrating the attacks, which killed almost 3,000 people, or even of faking them.
High on the list of distorters of what happened were those who argued that the perpetrators were not Al Qaida terrorists, but the Jews or Israel. Claims included the suggestion that Jews had been warned not to go to work that day, or that Mossad had staged the attacks as a way to build up support for Israel.
According to the ADL, despite a decade of evidence and similar attacks in other parts of the world, those theories have not disappeared.
"A new chorus of voices – who claim not to be anti-Jewish but simply anti-Zionist – have become the most popular promoters of these ideas," said the ADL.
"While the prevalence of certain conspiracy theories has changed over the last decade, one constant has been the penchant to accuse Jews and Israel of planning and executing the 9/11 attacks."
What has changed is the way such distortions are circulated – now typically on video sharing and social networking sites. In addition, immediately after September 11, those who expressed such antisemitic theories were likely to be white supremacists on the extreme right.
Now, the ADL said, they tended to be anti-Israel activists for whom September 11 was one of many Israeli actions carried out "to manufacture a war against its Muslim enemies".
"It is shocking that nearly a decade after 9/11 we are still confronted with those who continue to deny the historical record of 9/11 or who hold fast to antisemitic myths about that horrific day," said ADL national director Abraham Foxman.
"One of the saddest outcomes of 9/11 is that despite the fact that this national tragedy that brought so many Americans together, there remains this small group of vocal bigots who, nearly a decade later, are still seeking to promote and sell their own sinister agenda of blaming Jews and Israel