I will be referencing Tamyrlin a couple times in this post.

Tamyrlin had a long WoT-related chat with Brandon, Mr. Mystborn, Sanderson during their recent drive. One of the things Sanderson revealed is that the Finns have a large collection of ter'angreal and other One Power items at their disposal. Sanderson further clarified that this is how they grant visitors what they ask for.

I have wondered, since reading this transcript, if his provides any more possibility that Lanfear killed Asmodean. The Finn, based on their knowledge of the future, may have known precisely where Asmodean was in the Caemlyn royal palace. Using a ter'angreal, they could have opened a gateway up to that exact location. Without letting Lanfear escape, they could have let Lanfear kill Asmodean from beyond the gateway. Then they could have closed the gateway and kept Lanfear as a prisoner. The Finns may not have even let Lanfear channel during this encounter, instead using ter'angreal.

The one objection I saw in other threads was that Lanfear may have already been granted her three wishes. But this objection is not yet proven. One again, I will reference an old interview between Tamyrlin and Robert, Mr. Conan, Jordan.

"Tamyrlin: Did Lanfear get the opportunity to ask the 'Finns, to make a wish, after going through the doorway with Moiraine?
Jordan: Read and find out.
Tamyrlin: Okay, well, then did Moiraine get the opportunity to make a wish?
Jordan: Read and find out."

Based on this interview, we still do not know what happened to Lanfear and if she had her wishes from the Finns or not.

Based on similar logic, I am not sure if we can rule out Moiraine as an Asmodean-killer either. Moiraine had some knowledge of the future via her previous visit to the 'Finns and from her pilgrimage to Rhuidean. Could Moiraine have learned that she needed to kill Asmodean?

Based on these new possibilities that Sanderson has hinted at, does anyone not think it is too early to close the book on Lanfear as a suspect?

Of course, the age-old debate always is reduced to "Why would Lanfear have chosen to kill Asmodean when she appeared more mad at Rand and Aviendha?"

The only possible answer I can provide is that Lanfear allowed herself to cool down once she realized what a terrible predicament she was in. She knew that the Great Lord would not be pleased if she tried to kill Rand. Therefore, she decided to atone for her mistake by choosing to kill Asmodean. In her mind, this was one of the only ways that she could have still apeased the Great Lord. Lanfear knew that if she could not escape the Finns that she would most likely have to commit suicide and have her soul transmigrated by the Great Lord. Lanfear needed to gain some favor with the Dark One again before she comitted suicide. That is the best theory I can come up with as to why Lanfear may have chosen to kill Asmodean over Aviendha or Rand.