'Suspected murder,' Detective Chief Inspector Harry Nelson says quickly.

'Yes, yes,' says Phil, just as quickly, shooting a look at Ruth as if to say, 'Look at me talking to a real detective.'

Ruth keeps her face impassive.

'This is Doctor Ruth Galloway,' says Phil. 'She's our forensics expert.'

'Pleased to meet you,' says Nelson without smiling. He gestures towards the locked door of Ruth's office. 'Can we?'

Ruth slides in her key card and pushes open the door.

Her office is tiny, barely six feet across. One wall is entirely taken up by bookshelves, another by the door and a third by a grubby window with a view of an even grubbier ornamental lake. Ruth's desk squats against the fourth wall, with a framed poster of Indiana Jones – ironical, she always explains hastily – hanging over it. When she has tutorials the students frequently spill out into the corridor and she props the door open with her cat doorstop, a present from Peter. But now she slams the door shut and Phil and the detective stand there awkwardly, looking too big for the space. Nelson, in particular, seems to block out all the light as he stands, scowling, in front of the window. He looks too broad, too tall, too grown up for the room.

'Please…' Ruth gestures to the chairs stacked by the door. Phil makes a great performance of giving Nelson his chair first, practically wiping away the dust with his jumper sleeve.