“There must have once been a real Alan Grady,” he said.“Perhaps your father stole his identity. Perhaps the real Alan Grady died.”

Or he was murdered, I thought. Should I tell him, I wondered, about the Willem Van Buren passport? On balance, I thought not. Not yet.

“So tell me about this microcoder,” I said.

“Seems you know already.”

“I know it can be used to write numbers onto RFIDs,” I said. “But so what? Why was it worth chasing my father halfway round the world to get it back?”

“Fraud,” he said.

“Yeah, I assumed that, but what sort of fraud?”

“Making one horse appear to be another,” he said.

“But so what?” I said again. “Everyone knows that running a ringer in a race needs a conspiracy. Too many people would surely recognize the animal, and someone will spill the beans.”

“Ah yes,” he said. “But you could easily sell a foal or a yearling as another, with no risk then of anyone recognizing it as the wrong horse. Especially if you sell it to England from Australia or vice versa.”

“But surely horses are DNA tested for their parentage,” I said.

“They are,” he agreed. “But they are only retested if they eventually go to stud. And the DNA testing takes a long time. Not like using a handheld scanner on the ID chip, which is instant.”

“But even if you switch a bad horse for a good one and then sell it,” I said, “what would you do with the good one you’ve kept? You can’t sell the same horse twice.”

“No, but you could put it into training under its new identity. It would still be a good horse and could make a packet on the track. And if it’s so much better than people think it should be, it would win at long odds, at least to start with. Just make sure you don’t breed it. Geld it, even, to be safe.”

“And the bad one you sold would just be seen as another expensive failure?” I said. “And there are lots of those about.”

“Exactly,” he said.

Everyone in racing knew about Snaafi Dancer. Bought as a yearling in 1983 for a world’s record price of over ten million dollars, he ran too slow to ever make it to the racetrack, and then turned out to be infertile. And he was just one of a whole string of flops that had been sold for millions and then earned not a cent of it back.

“I grant you, it’s a long-term strategy,” he said. “But one that’s quite likely to be profitable. Obviously, you wouldn’t do it with a really megavaluable yearling, as there would be masses of checks made, but loads of horses go to the sales each year. And even the Horses-in-Training Sales now attract huge prices, and for geldings too.”

“But I thought those ID chips were meant to be secure and unchangeable,” I said.

“So did we,” he said. “But it seems we were wrong. The chip that’s inserted in a horse’s neck contains a number that is unique for that horse, and it is supposed to be read-only and permanent. But someone has discovered that a very intense localized magnetic field can wipe the number from the chip, just the same way those security tags stuck on CDs in shops are wiped over a magnetic pad to clear them.”

“And, don’t tell me,” I said, “the microcoder can write a new number in?”

“Well, not quite,” he said. “The magnetic field has to be so strong that the chip’s electronics are completely destroyed. But the microcoder can write a different number into a new chip, which is then inserted in the horse’s neck and, hey, presto, you instantly have a different horse.”

“But how about the horse’s passport with all its whorls and such?” I said.

“That would be OK if people bothered,” he said. “But too many people believe the technology without question. Like in tennis. All those arguments about whether the ball was in or out have disappeared thanks to the computerized Hawk-Eye system. The players believe it absolutely, as does everyone else. If Hawk-Eye says it was out, then it was out. Same with this. If the ID chip says that the animal is horse A, then it’s horse A, even if it’s got all the whorls for horse B. The authorities try to get people to check both, but they still tend to believe the ID chips. After all, it’s the same authorities that insist on them being inserted, and then they tell people they’re foolproof. Only now they find they’re not.”

“Does everywhere use the same ones?” I said.

“Pretty much,” he said. “Except the United States. They don’t use chips at all, at least not yet, because they tattoo the inside of the horse’s lip. But if a horse comes from the States to race in Australia or Europe, it has to be chipped first.”

“By whom?” I said.

“A vet authorized by the racing board.”

“Seems to me that the system needs changing,” I said.

“We need that microcoder back,” he said in reply.

“What’s to stop someone making another one?” I said.

“Nothing, I suppose,” he said. “But our boffins say it’s not that easy.”

“How about the man who made the first one? He could surely make another.”

“Ah,” he said. “Therein lies a tale.”

“What tale?” I asked.

“A trigger-happy Victoria State policeman shot him as he was trying to resist arrest.”

“Dead?” I asked.

“As good as,” he said. “Got a bullet in his brain. Totally gaga.”

What a waste, I thought. Smarter than the boffins, and now what? A vegetable.

“Someone else will work it out,” I said.“Probably some fourteen-year-old in his school science lab.” Or Luca, I thought.

“It would have to be someone with both the knowledge and the intent,” he said.

“If there are any with the knowledge, then there will be some with the intent. Trust me, I’m a bookmaker.”

He laughed. “You’re probably right. But we have to try and do what we can to stay ahead of them.”

“How about the tattoos the Americans use?”

“They’re tricky to do, and they become difficult to read as the horse gets older,” he said. “And they’re not fraudproof either. It has been known for some unscrupulous souls to try to vary the original tattoo.”

We had been sitting in the rest area for quite a while, and, as we talked, I had been trying to think what to do. Why had he said nothing about the money? Did he, in fact, know that the money had also been in the rucksack? Was I going to give him the microcoder and the cash? Did I have any choice in the matter? If John here had a direct line to the Victoria State Police, then he probably did to Detective Chief Inspector Llewellyn as well. But why then had he entered my house uninvited through a window in the middle of the night?

“Never mind the horses,” I said. “Do you have any personal ID?”

“What, here?”

“Yes,” I said. “How do I know you are who you say you are?”

“I told you,” he replied slightly uncomfortably. “The Australian Racing Board would deny all knowledge of my existence.”

“And why is that, exactly?” I said.

“The very nature of my job means I have to work undercover. If I was a normal employee, then my cover would be blown. There are bound to be some people within the organization who would pass on the information to the very people I am trying to investigate.”

“But John who?” I said.

“Smith,” he said with a straight face.

John Smith. Oh yeah, I thought, pull the other one. But John was probably not his real name either.

“So where exactly is my microcoder?” he said.

“I gave it to a friend.”

“You did what?” he exclaimed. “Who?”

“A friend who’s an electronics specialist,” I said. “To try and see what it does.”

He went pale. “Well, get it back now,” he almost shouted.

“I can’t,” I said. “My friend has gone away on holiday for a week. To Greece.”

I didn’t know why I was so reluctant to simply hand it over. I suppose I thought that this John would then just disappear, in which case I would never learn anything more about my father. Maybe it was also because I didn’t really trust him. Not enough to hand over my trump card to him, not just yet anyway.