Sam Rockwell and Saoirse Ronan are the stars of this film.
In the role of Constable Stalker, Saoirse Ronan produces innumerable red herrings which move the plot forward. The murder victim is hit in the face with a pair of skis from the performance of "The Mousetrap" and as she says it is "all downhill from there".
I will not give any spoilers about Sam Rockwell.
Although it is a comedy, it does reference some of the serious issues of the time in which it is set.
It is set in a period of history when female officers had a struggle against the institutional sexism of the met. A struggle which is not over today.
Her very name suggests the Stalker Inquiry which was an investigation into the shootings of suspected members of the Provisional Irish Republican Army (IRA) by the Royal Ulster Constabulary in 1983.
Overall it is a very satisfying "whodunnit" in the Agatha Christie tradition and a very good comedy to boot.