The Pillowman, Bear Pit Theatre, Stratford-upon-Avon, until 29 June.
From scene one it's clear that we're in for a twisted evening as protective-suited scenes-of-crime officers break into a happy dance while wiping blood off a table.
Who's done the blood-letting though? Is it Katurian, writer of luridly ghastly, and supposedly fictional, tales of child-killing and mutiliation? Or perhaps his sister Michaela, acting out those gross fantasies for real? Or even the two detectives, Tupolski and Ariel, interrogating them on behalf of a totalitarian state with absolutely no compunction in doing away with anyone who transgresses?
Graham Tyrer, as chief interrogator Tupolski, conjures up a performance of real menace as he plays cat to Katurian's mouse. Hannah McBride is all too believable as the clearly disturbed Ariel, giving vent to her sadistic vengeance fantasy, while Alexander Simkin is never less than convincing as the writer who will accept death as long as his writing survives.
Director Steve Farr cleverly builds the tension as the characters play out this danse macabre. But somehow, for this hapless witness at least, a deeper truth goes missing somewhere.
Martin McDonagh's play may be a furiously foul-mouthed, wince-inducing horror story, but is there very much more to it than that? Not a lot.