‘She got back earlier this evening. I think she might have gone straight to bed and doesn’t know yet about the shooting.’

While Drummond made the call I looked out of the window. My heart was booming in my ears. I was struggling to get a handle on my emotions. Dark thoughts were swirling through my head, each one adding to my anxiety.

Dave Prentiss’s murder. The warning that more of us were going to be targeted. The fear in Aidan’s voice. The fact that the killer was now on the loose in London. For all I knew he was already standing outside our house in Balham. Ready and waiting for an opportunity to kill Aidan. Or perhaps he would go after my mother next. Strike when she appeared at a window or left for work in the morning.

The thought of it was burning me up inside, making me feel sick. Surely more needed to be done to protect them. To keep them from being killed.

Getting marked cars to park outside our homes was only a short-term measure. It couldn’t go on indefinitely. But protecting all the detectives and our families was going to be a huge problem, given that we couldn’t all stay indoors until the threat went away.

As Drummond had pointed out earlier, providing round-the-clock protection for everyone would be a mega commitment. Small teams of officers would have to be assigned to each individual and for us detectives that would be completely impractical. We simply wouldn’t be able to do our jobs.

And the same would go for our loved ones. Would Aidan be able to teach? Would the school even want him to turn up for work, knowing he was on a killer’s hit list?

We had all been hoping and praying that we were dealing with an empty threat. That we wouldn’t have to confront all those difficult-to-solve issues. But now we knew it was real and that meant we had to deal with it, along with the inevitable tsunami of fear and panic.

‘We need to pull in all the likely suspects,’ Drummond said, coming off the phone. ‘And that includes the villains who have the clout to hire a contract killer. It’s my firm belief that Dave Prentiss was murdered by a pro.’

‘It has to be possible that the killer is the same person who sent the messages,’ I said.

Drummond nodded. ‘I agree it’s possible, but I think it’s unlikely. This doesn’t feel like the work of a one-man-band to me. It has to be someone like Roy Slack. He’s got the motive, the bottle and the money to pay someone to do his dirty work.’

‘There was nothing incriminating on his phones or laptop, guv,’ I said. ‘In fact they’d hardly been used. And we had a good look round his office and flat.’