‘Tansy must’ve started hammering on the window immediately after Landry fell past her. You weren’t expecting your wife to start screaming and banging on the glass, were you? Understandably averse to anyone witnessing your bit of domestic abuse, you opened up. She ran straight past you, screaming her head off, out of the flat, and downstairs to Derrick Wilson.

‘At which point you looked down over the balustrade and saw Lula Landry lying dead in the street below.’

Bestigui puffed smoke slowly, without taking his eyes off Strike’s face.

‘What you did next might seem quite incriminating to a jury. You didn’t dial 999. You didn’t run after your half-frozen, hysterical wife. You didn’t even – which the jury might find more understandable – run and flush away the coke you knew was lying in open view in the bathroom.

‘No, what you did next, before following your wife or calling the police, was to wipe that window clean. There’d be no prints to show that Tansy had placed her hands on the outside of the glass, would there? Your priority was to make sure that nobody could prove you had shoved your wife out on to a balcony in a temperature of minus ten. What with your unsavoury reputation for assault and abuse, and the possibility of a lawsuit from a young employee in the air, you weren’t going to hand the press or a prosecutor any additional evidence, were you?

‘Once you’d satisfied yourself that you’d removed any trace of her prints from the glass, you ran downstairs and compelled her to return to your flat. In the short time available to you before the police arrived, you bullied her into agreeing not to admit where she’d been when the body fell. I don’t know what you promised her, or threatened her with; but whatever it was, it worked.

‘You still didn’t feel completely safe, though, because she was so shocked and distressed you thought she might blurt out the whole story. So you tried to distract the police by ranting about the flowers that had been knocked over in Deeby Macc’s flat, hoping Tansy would pull herself together and stick to the deal.

‘Well she has, hasn’t she? God knows how much it’s cost you, but she’s let herself be dragged through the dirt in the press; she’s put up with being called a coke-addled fantasist; she’s stuck to her cock-and-bull story about hearing Landry and the murderer argue, through two floors, and soundproofed glass.

‘Once she realises there’s photographic proof of where she was, though,’ said Strike, ‘I think she’ll be glad to come clean. Your wife might think she loves money more than anything in the world, but her conscience is troubling her. I’m confident she’ll crack pretty fast.’