"Well, there's a murder more than every two weeks. If he can solve each in less than two weeks, I'm sure the folks back home would be happy to let him go through the cold cases as well," he says, smiling gently. "Or do you only do the weird ones?"

It's not quite a fair count, of course. Plenty of these murders have very little mystery to them, and it's all about documenting the evidence.

He enjoys the challenge too, of course he does. But more than that, he enjoys putting dangerous people behind bars, and making the world a slightly safer place.