:This rumors are encyclopedic since they are correctly presented as "rumors" not facts. They reached the press, caused some stirr, so they are notable. The article does not say he was "Antonov", it says only that there were notable allegations.  

 :To give you an analogy, there are rumors that Russia was behind Yushchenko's poisioning and that it sent Spetznaz to help Yanuk. This is presented in Wikipedia in exactly same way, as rumors and allegations that reached the press. On the other hand, the posioning itself is not a rumor. It is presented as fact, as it is widely considered proven. Do you note the difference?