Question about an episode. Vick's chip

How did sarah know for a fact that Derrik had killed Andy Goode. There wasn’t even a clue to it. Where did her threatening him at the end of the episode come from? She just went into the shower to tell him about the Turk meeting… and called him out and threatend him. I rewatched the episode again to look for the clue and there wasn’t a one. Please Help!!!