‘There’s one last thing,’ Ailsa said. ‘There’s a substantial amount of bruising beneath the handcuffs and cable ties. It’s very area specific and wasn’t apparent on the surface of the skin owing to discolouration of the corpse, but it appears that Mrs Hawksmith struggled. Now, playing devil’s advocate, I could say that perhaps she made all these preparations then changed her mind too late, but the bathwater stayed in a long time. We know that because of the tidemark and because of the water inside the body. If she changed her mind, though, why not pull the plug at least, in the hope that her wounds might clot, buying her time until she was found?’

Ava thought back to the bathroom.

‘The plug was between her feet, a normal rubber plug on a chain, right?’

Ailsa turned back to the counter behind her, picked up a large photo and handed it to Ava. In it, the plug was clearly visible still in the hole.

‘Any physical reason why she couldn’t have sat up to pull that plug out?’ Ava queried.

‘No. Mrs Hawksmith likely hadn’t done any sit-ups for a couple of decades, but she could have pulled against the binding around her ankles. She was fit enough to have done that once and to have reached the plug, particularly given that her ankles were bound to each tap, leaving the necessary space between her legs.’

‘So why didn’t she?’ Ava mused.

‘That, my dear, is your question to answer.’ Ailsa snapped off her gloves. ‘Do I need to take another look at the wound on your leg, or can I trust that you’re taking better care of yourself?’

‘I am, I promise. I’m even eating five portions of fruit and vegetables a day,’ Ava murmured, removing her own gloves and depositing them in a bin.

‘Probably best to minimise the lying. It’s not your strong point,’ Ailsa reprimanded gently.

‘I need to get back and brief the team.’ Ava smiled and reached a hand out to touch Ailsa’s shoulder.

‘And I have families waiting for explanations that won’t make them feel any better at all. Before you go, Stephen Berry. The tox results came back. He had high levels of selective serotonin reuptake inhibitors in his body.’

‘In plain terms?’

‘Antidepressant medication. If you block the reabsorption of serotonin into the brain, there’s more available in the body. Keeps you feeling more positive and works against the depression. It’s commonly prescribed for bipolar disorder and it’s in line with the medical notes provided by his doctor. Given the fact that we now know he’d recently attempted suicide, I’m going to sign it off as a deliberate taking of his own life. Wherever the bruise on his middle finger came from, there’s no corroborative evidence to suggest the death was suspicious.’