With a shadowy colleague looking on, the team starts poking holes in the evolving story of a combative suspect accused of poisoning her brother-in-law.
Called in one by one on a Sunday, the team risks a legal entanglement when a routine interview with a convicted killer's wife takes a provocative turn.
Asking increasingly pointed questions, the team tries to crack a zealous defense put forth by the head of an online group that unmasks sexual predators.