A similar entry appears in the Wheel of Time Companion confirming the information available in the main story arc.
Author: Leora Oldessroth
Varadin is a Whitecloak spy in Tanchico who operates under the disguise of being a rug merchant; he sends word to Pedron Niall by pigeon that the Seanchan have overrun the city. Pedron Niall believes his descriptions of the Seanchan and their creatures to be the disjointed writings of a sick man (LoC, Ch. 9).
When Varadin sends a second message to Niall, and tells him he is hiding Asidim Faisar (whom he is not supposed to know about), Niall begins to take Varadin more seriously (LoC, Ch. 31). Niall receives a report from Asidim Faisar verifying what Varadin has said about the Seanchan (ACoS, Prologue).