The Best and the Brightest

A research student dies in a university science lab, and the cause is anaphylactic shock brought on by food that should not have harmed her. Traces of highly concentrated nut oil at the scene say the rest: her food was deliberately contaminated. The killing is careful, almost clinical, and there is no obvious motive attached to it. Then a second student dies the next day in what looks like an accident, and the pattern settles in.

Burke and the team are left with the worst possible answer. The killer is inside the university, someone who moves through the corridors and lecture halls with a face nobody questions. A place built around learning and open doors is a strange backdrop for this kind of malice, and the episode leans into the gap between the intellectual calm and the violence underneath. The investigation becomes a search for the one person in the room who does not belong there, except they look exactly like everyone else.

Glenn Chandler and Robert Fraser wrote it, James Henry directed. Alex Norton's Burke heads the enquiry with Blythe Duff's DS Jackie Reid, John Michie's DI Robbie Ross and Colin McCredie's DC Stuart Fraser. Seamus Gubbins is Professor Sean Murray, Maimie McCoy is Jessica Flowers, Jenny Foulds is Ruth Haines, Matthew McVarish is Miles, and Harmage Singh Kalirai and Nila Aalia play Ashraf Hassan and Mrs Hassan.

The forensic detail is solid, but the real chill is the insider threat. A killer who knows the building and everyone in it is harder to catch than any stranger, and the show keeps that worry close. University politics, as anyone who has worked in one knows, can be its own kind of blood sport. And it is a reminder, if one were needed, that murder does not need a dark alley. A lab coat and a clear afternoon will do.