‘Not any that was prescribed; although it’s possible she was taking non-prescription drugs. The tox screen will give us more details. I’ve checked with the Scenes of Crime team. There was no medication, legal or otherwise, found at the flat, other than standard over-the-counter stuff, and they were out of date with some still in the pack.’

‘So no sign of addiction, then.’

‘None,’ Callanach agreed.

They stared at one another across the desk. Ava studied her fingernails, still ragged from clutching the wall at Tantallon, and wondered who was going to say it first. Callanach let her do the honours.

‘You don’t think …’ she said slowly.

‘It has to be a coincidence,’ he replied. ‘Because otherwise you and I are going back to Tantallon, and back up on that fucking wall.’

‘It’s rained almost non-stop since the night Stephen Berry died. The chances of us picking up anything useful now is slim, but I think we have to try.’

‘Ava, we already have one victim from the nursing home and Fenella Hawksmith. Are you sure about this?’

‘Stephen Berry attempted suicide a few weeks ago, now he’s dead following a long drop from a castle wall in the middle of the night. Think about it. The chemicals in his body that showed up on the tox screen confirmed that he hadn’t gone off his meds. He was doing what his doctor had instructed him to do. There should have been enough serotonin in him to keep him steady, if not what you and I would think of as happy. He had a girlfriend, right?’

‘Ex,’ Callanach confirmed.

‘So let’s talk to her, confirm his movements and moods between the attempt from the Queensferry Crossing and his trip to Tantallon.’

‘I’ll get Tripp on it,’ Callanach said. ‘Anything concrete regarding Mrs Hawksmith’s daughter yet?’

‘No death certificate,’ Ava said. ‘So either she’s still alive, is dead but wasn’t identified, or is dead but hasn’t been found.’

‘How are you going to persuade Overbeck that we need to investigate the Berry death as a possible murder?’

‘I’m not,’ Ava said. ‘I shall be engaging a secret weapon. You don’t need to worry about it.’

‘You’ve got a secret weapon you’re not prepared to share with me? That’s hardly fair.’

‘Believe me, you don’t want any part of it. And in case you’re wondering, Pax Graham’s team are proceeding on the assumption that the Bruce Jenson killing was committed by a staff member. Forensics has shown the initial blow to the glass door was from the inside and that afterwards someone hit the fractured area from the outside. They’ve concluded it was an attempt to make it look like an intruder.’

‘Motive?’ Callanach asked.