Mindgame by Anthony Horowitz
When Mark Styler, a writer of glossy 'true crime' paperbacks, tries to get an interview with Easterman, a notorious serial killer, he has no idea what he's walking into. First he has to get past Dr Farquhar, the quixotic head of Fairfields - the asylum where Easterman is kept. But soon he discovers that nothing is what it seems. Who is the mysterious Borson? Where did he get the meat in the fridge? And why isn't the skeleton in the closet? Mindgame is a puzzle-box of a play. A dazzling thriller and a jet black comedy that twists its way towards a shocking conclusion. Reading the text is the only way to uncover all the clues.