Celia explained that she had been the records manager at a freight auditing contractor linked to Vincent’s company.

Walter had sometimes come to her office asking for invoices, especially during the year before his death.

She had found Joan through a former colleague after news of the renewed investigation reached her.

‘I didn’t know he had a daughter who was looking into this,’ she said.

‘I knew he was trying to protect himself.

There is a difference, and I wish I had understood it sooner.’

She slid a single photocopy toward me.