Manslaughter

A respectable superintendent walks into a station and confesses to killing his wife. It was a crime of passion, he says, manslaughter rather than murder, and on the face of it the CIB could wrap this one up before lunch. Clark isn't having it. The case looks too much like one Lindsay investigated himself five years earlier, and patterns like that are rarely coincidence.

Rob Heyland wrote it, Alan Dossor directed, and the episode is a study in police privilege. Lindsay, played by David Hayman with the weary authority of a man used to being believed, trades on that presumption. The affair with his sister-in-law, Gail Myles, played by a young Hermione Norris years before Spooks and Cold Feet, gives him motive. The post-mortem turns up the evidence that matters. And through it all Connell is convinced he's rigged the circumstances to walk free, with Clark under pressure to get the right result before time runs out. The episode has the shape of a closed case being slowly reopened, and the pleasure is in watching the certainty leak out of it. Lindsay's version of events holds together until it doesn't, and the show makes you wait for the crack.

The support is as solid as the guest lead. Hugh Ross's Cmdr. Graham Sullivan and Paul Bentall's Chief Supt. Powers keep the departmental side credible, and Jason Watkins, early in a career that would take him all over British television, is the Custody Sergeant.

What gives the episode its bite is the mirror at the heart of it: a senior officer who once investigated a killing, years later standing accused of the same shape of crime. The point lands without being hammered home. A man who knows the system is assumed honest until the evidence says otherwise, and the evidence takes its time.