Why do they want Nikki?? (spoilers)

What's the point of them trying to kill Nikki? She wasn't (and still isn't) aware of their operation, nor was Ray, and he's a non-factor now. I remember they wanted to take him out but Emmit beat them to it, but if i remember correctly it wasn't for knowledge of their business, but constant interference with his brother which was also bringing more unwanted police attention to Emmit.

She just knows that two guys beat her when she was meeting with Sy. So now they have her framed for murder to divert attention away from Emmit, she's not talking and the new police chief doesn't want to hear what she has to say anyway. Flipping a police bus and killing multiple passengers/cops to assassinate a prisoner brings a whole lot of attention, rendering the frame job useless.

Am I forgetting something? Did I miss her having some knowledge of Varga and friends beyond the fact that a Cossack and an Asian viciously beat her? (Her wounds, mind you, blamed on Ray to fit the fed up battered wife narrative of the police chief) All loose ends would have been tied up if they left her alone on the prison transport bus.