‘All right, Carl. Get back here as soon as you can,’ Gillard said. ‘I’ve changed my mind. I’m too short-staffed to keep you off the case.’ Gillard stared across the office, dozens of work-stations, almost all unmanned. The only other detective sitting there was Rainy Macintosh, just returned from the abortive surveillance operation, and with a long Friday evening ahead of her tracking Slater’s financial records. Rob Townsend wasn’t there, nor Claire Mulholland. She was still on her way back from the surveillance op. The three trainees would be going in an hour, their normal office hours over. An incident room meeting would be useful to throw out some ideas, but it was pointless. He’d be talking to himself. Everyone was strung out between too many simultaneous inquiries, of which nailing Slater remained firmly top priority. They had some clues. Credit card records showed the private detective had rented a vehicle from Europcar in Croydon the day after the murder of Blanchard, and returned it to an outlet in Redhill just yesterday. Redhill was on the train line to Gatwick Airport. Maybe he was trying to leave the country? That would be hard. The Met Police had his passport and that of his wife.

The big unknown was exactly who Slater had been working for. When he had first run into him at the Aqua Western HQ in Windsor, Gillard had assumed that Slater was working for the water company, on a secretive mission to track down the source of an embezzlement. Stella Anderson had confirmed that. For them, using a private detective made sense if they were worried about publicity. Gillard had assumed that if they had succeeded in finding Blanchard they would have paid him off, and tied him up in a non-disclosure agreement. The crucial regulatory overview might then proceed smoothly, the existence of the fraud buried.

But since the killing, Gillard no longer took that view. Even the most ruthless corporation would baulk at killing an employee, at least in a country like the UK. Once Ozzy Blanchard had been murdered, the suspicion fell on either the Tickett family or Arrowsmith. If Arrowsmith was bent, which seemed likely, then there was clearly an incentive to rub out his partner in crime. From Arrowsmith’s perspective, Ozzy Blanchard’s death had the dual advantages of removing a key witness to the fraud and providing a conveniently dead suspect on whom to hang the entire crime, a man who was in no position to protest his innocence. And Slater had been the instrument to make it happen. Gillard admitted to himself that he had underestimated Slater’s ruthlessness.

Even having given up the gun, the man was dangerous.