Stabbed to death while they slept, the killings of David and Elaine Lerner prove a mystery to DS Matt Davlin (Jamie Bamber) and DS Ronnie Brooks (Bradley Walsh). Universally loved, there’s not a single lead that points to grievances held or enemies made. The previous owner of their house soon emerges as a much more likely target for attack – Camilla Mallon, a banker embroiled in a hedge fund scandal.

Could the brutal murders be a case of mistaken identity?

As our Crown Prosecutors navigate this seemingly senseless crime, Jake’s old mentor Margaret Rumsfield (Jill Baker) argues that the accused should face only manslaughter charges. Without motive, without intent, can our heroes make a murder charge stick?

Guest-starring Samuel West.