Taggart (1983)

Season 22: Episode 9

When a research student is found dead in a university science lab following a severe anaphylactic shock, the evidence suggests that her food has been deliberately contaminated. Traces of highly concentrated nut oil are found at the scene, but there seems to be no clear motive for her murder. Then another student dies in a suspicious accident the following day and Burke and the team realise that a calculating killer is at work within the university.