Were Taim and the Ashaman behind the attack?
First, it was a very well organized and planned attack. It is done after Demira is shadowed and possibly lured (or even Compelled) into small, empty alleys. The attack is done by people meeting her. Simultaneously, a man appears bringing the message to her Warder at the Crown and Roses. The interception may mean that other people directed the “Aiel” to their position and cleared the alleys, giving 10-20 people participating, of which at least a few must know Caemlyn very well or that some channeler was part of the group. Furthermore, the attackers must have intercepted the message to Demira’s informant. There’s reason to believe that Compulsion was used: “Turning away from the gate, her [Demira’s] eyes chanced to meet those of a tall, lean-faced fellow in a carter’s vest who was gazing at her much too admiringly. When their eyes met, he winked! She was not going to put with that all the way back to the inn…. She slipped into the narrow shaded gap between a cutler’s shop and a tavern.