Killer by the Lake

Episode 4 (1x4)

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After their first operation fails, the cops and paramilitary police take the risk of setting a new trap for the killer by using Marina, an officer on Clovis' team, as bait. Living with Lise's mother Marianne becomes unbearable at home, a situation worsened by the couple's relationship crisis since Lise has been doubting her husband's honesty. She continues her research and discovers the existence of another woman named Mathilde. Clovis is leading a double life.