Something clicked in his memory. He took out his mobile and rang PC Soraya Shah, the Thames Valley Police family liaison officer who had looked after Francesca Arrowsmith while her husband had been abducted. After greeting her he said. ‘Soraya, you recall the Italian holiday home of Kelvin Arrowsmith?’

‘Yes, sir.’

‘Can you dig up the address for me, and any photographs of the place?’

‘I’ll get right on it.’

It was less than ten minutes later when she rang back. ‘I’ve emailed you the details, sir. There were dozens of photographs of the villa on Francesca’s phone. She’s back in the house now, and her phone has been returned to her, so I can’t look at anything she may have added in the last couple of days.’

‘That’s no problem.’ Gillard thanked her and hung up. He was beginning to get an idea as to how Arrowsmith had paid Slater – untraceably – for the hit on Blanchard.

Back at Mount Browne, Gillard did half an hour’s useful web searching before the Saturday afternoon incident room meeting. Shireen Corey Williams and a stressed-looking Rob Townsend were the first to arrive, followed by Rainy Macintosh, looking distinctly upbeat.

‘So how are we doing?’ Gillard asked. ‘Let’s start with you, Shireen. Connections between Ray Slater and Kelvin Arrowsmith.’

‘I’ve got all Ray Slater’s bank accounts, business and personal, savings both in his name and in his wife’s and, sad to say, it all looks totally legit. He was awarded the contract from Aqua Western in March, the agreed monthly retainer plus expenses have been made ever since. I’ve matched them up, and they were signed off not by Arrowsmith but by his boss Shane Devlin. It’s all itemised, and not unreasonable amounts.’

Gillard nodded. ‘Rob, how you getting on tracing Slater?’

‘The burner phone he left on the train had not been used for anything else. To be honest I’m struggling to find the time to think outside the box on this one. He’s obviously got lots of phones.’

Rainy Macintosh was looking rather smug at this moment, clearly dying to say her piece. Gillard let her.

‘I think I’ve got an answer, sir, or part of one anyway. As you know, the Met Police have Slater’s UK passport, seized from his home. But an Irish citizen named Raymond Slater flew out of Stansted to Naples two days ago. A woman named Anne Slater was on the next seat. She used a UK passport that had previously been reported lost. It’s the replacement document that the Met seized.’

Two different ways to get second passports. Gillard wasn’t surprised that a private detective would have this kind of precaution in place. ‘I know exactly where they’ve gone,’ he said. He described his discovery of Slater’s interest in Italy, which matched the region where Arrowsmith had acquired a holiday home.