This is my brothers theory: In the Great Hunt, page 412, right after Galldrians killed Dena, Zera tells Thom "If you mean Barthanes, its too late. HE is dead. His servants found him ripped to pieces.The only way they knew it was him was that his head was stuck on a pike over the fireplace." It could have been a gholam. When Fel was killed, he was ripped a part in the same manner. A Myrdraal could have done it. This is where it gets kinda whacky. The thing that killed Barthanes could have been after Rand, or the Horn. (Remember, it hadn't been blown yet, and Rand had just left the othernight.) Killing Barthanes took out a major contender for the throne. There were Forsaken everwhere--Andor, Tear, Illian, the Tower. So, any Forsaken might have been pulling strings in Cairhien and sent the gholam. These things are mere speculation, but if they are true, then we can connect the early story, where Moirane is explaning everything, to the latest versions (CoS, PoD) and maybe come up with a few more facts.