No there is many indicators that Mossad is the most likely sponsor. His well established link to Ehud Barak the ex-PM who has deep extensive intelligence history is an example. It would be extremely long post to detail all the evidence.

It’s not unreasonable to suspect he successfully compromised both a sitting US president and the son of the Queen of England, and that is only the beginning of the list.

Which intel agency is most likely? Obviously Mossad should be at the top of the list ... but yeah OK let’s remove it, I’m anti-semitic.