Beauvoir explains that the only way to melt ice on a subzero day is to spill a substance that resists freezing. The killer poured windshield wiper fluid on the frozen lake to create a puddle. The investigators still can’t figure out how the lawn chair was wired for electricity. CC’s husband is an inventor, so he may have found a way, but Gamache doesn’t want to assume he’s the murderer yet.

None of the detectives have been able to find any information on CC that goes back farther than 20 years. Gamache suggests they check on her parents, Eleanor and Henri de Poitiers. He also asks them to research Li Bien, CC’s philosophy of life.

Gamache says he’s going to find CC’s photographer because he may have unknowingly taken a picture of the murderer. Agent Yvette Nichol, newly arrived, announces that she’s already found Saul Petrov. Everyone on the team seems shocked to see her.

Gamache is angry at Agent Nichol’s arrival. Beauvoir shares his boss’s view; he considers her a:

[…] rancid, wretched, petty little woman who’d almost ruined their last case, and had proved a deeply divisive element in a team that thrived and depended on harmony (155).