It had a nice ring to it, Li thought. Brain fingerprinting. It wasn’t about collecting evidence left at the scene by the criminal, it was about reading the print the crime had left in the culprit’s brain.
‘Now, I don’t want to get technical about it,’ the professor said, ‘because it’s a highly complex piece of science. But the essence of it is this: if you are shown something that you recognise, there is a unique electrical response in your brain. It doesn’t matter if you deny recognising that something or not. Your brain’s response is always the same. You have absolutely no control over it. And you know what?’ They all waited eagerly to know what. ‘We can read that response. We attach sensors to your head, entirely non-invasive, and plug you into our computer, and we will know what you know and what you don’t.’ She waved her hand airily towards the ceiling. ‘Which is as much good news for the innocent as it is bad news for the guilty. Because we can rule you out, just as certainly as we can rule you in.’
She stood up and clasped her hands and seemed for a moment transported to another place. She began walking slowly around the room as if addressing students in a lecture room. ‘We call that unique electrical response a MERMER. It’s an acronym. It doesn’t work in Chinese, so there’s no point in me trying to explain. It’s just what we call it. I learned about MERMER from its inventor, who was my professor at university in the United States. Doctor Larry Farwell. A very smart man. Smart enough to recognise that I was smart enough to invest his time in. And now here I am, back in the land of my ancestors, developing a uniquely Chinese version of the process that could revolutionise criminal investigation in the People’s Republic. In every test carried out to date it has proven one hundred per cent successful.’ She spun around to face them, eyes wide. ‘But I don’t want you to take my word for it. I want to prove it to you. Because we need your support for the funding that will make this process available to every criminal investigation department in the country.’
It was a very slick and persuasive presentation, and she had been in the room for less than ten minutes. There wasn’t one of the senior law enforcement officers present who didn’t want to believe her.
‘I’m going to demonstrate just how effective MERMER is by subjecting you to a test that I developed for work with my students,’ she said. ‘My assistant and a team of graduates will prepare you for it. You will be split into two groups of three. One group will be briefed on a specific criminal scenario, the other will not. I will be unaware which of you is in which group. But afterwards, when I test you, your brain will provide the answer for me. And I won’t need to ask you a single question. All you will have to do is look at some photographic images on a computer screen while I monitor your brain’s response. And the reason it’s foolproof?’ She held out open palms and smiled, as if it was simplicity itself. ‘Your brain just can’t lie.’
II
Li sat on a stool at a science bench in a darkened room with Procurator General Meng and Commissioner Zhu. Blinds were drawn on the window, and the only light in the room was a desk lamp that focused their attention on a spread of grim photographs arranged on the benchtop. They were colour eight-by-tens of a particularly bloody crime scene. Most crime scenes now seemed all too depressingly familiar to Li. This was no different. Two women and a young man stripped naked and lying side by side by side at odd angles on the top of a makeshift bed. The covers were soaked red by their blood, the dark brown-red of long dried blood. It was smeared on their bodies, and their trunk wounds were gaping dark holes, like so many black beetles crawling over them. Li recognised them as knife wounds. There was a close-up of the male. The back of his head was missing, as if a bullet fired through the front of it had taken the back away as it exited. But he was lying face down, so it was impossible to see the entry wound.
The room had been shot from various angles. It appeared to be a bedroom. Drawers had been pulled out of chests, and contents strewn about the floor. There were curtains on the window, but one of them had been pulled free of its rail at one end, the hem of it clutched in the hands of one of the dead women.
Beyond the light, and flitting back and forth on the periphery of their vision, one of Lynn Pan’s graduate students was laying more photographs in front of them.
‘I want each of you to imagine that you are the murderer,’ she was saying, ‘and that this is the scene you have left behind you.’ More photographs. ‘This is the house. You can see it’s a small dwelling in a suburban area of the town.’ A row of featureless white-tile dwellings was shaded by a line of trees. ‘You can see something lying in the drive. Something you took from the scene and dropped there.’ She laid another photograph in front of them, and they saw that it was a white shirt, torn and bloody. She reached down behind the bench and lifted up a large, clear plastic evidence bag with the bloody white shirt sealed inside.
‘Is this a real crime scene?’ Procurator Meng asked looking with distaste at the shirt. It was a long time since he had been actively involved in crime scene investigation. ‘I mean, is that real?’
‘Of course,’ said the assistant. ‘We wouldn’t have the resources to mock up something like this.’ She lifted another evidence bag on to the counter top. It contained a serrated hunting knife with a bone handle. ‘And this is the weapon you used to commit the murders. You can handle it if you like.’
Li lifted the bag and removed the weapon carefully from inside. He ran the blade lightly across the flats of his fingers. It was still sharp. It was heavy, but nicely balanced. Not a cheap knife. A professional hunter’s weapon. Two inches of the blade at the hilt was serrated. He looked up and found Commissioner Zhu watching him. ‘Don’t let it give you any ideas, Li,’ he said.
Li smiled, flipped the knife over, and held it out to the Commissioner, handle first. Beijing’s top cop took the proffered weapon and examined it carefully. Li watched him handle it with the confidence of one used to knives. ‘You look like you were born with one of those in your hands, Commissioner Zhu.’
The Commissioner looked at him, surprised. ‘Is it that obvious?’
Li shrugged. He wasn’t sure what the Commissioner meant. ‘You just seem comfortable with it, that’s all.’
The Commissioner smiled. A rare sight that Li had seldom seen. ‘It’s been a long time,’ he said. ‘In Xinjiang Province, where I grew up, my father hunted deer in the forest. My earliest memories are of going hunting with him. Of course, we had no guns. We set traps, with salt as bait, and killed the animals by slitting their throats. My father taught me how to gut a deer in under ten minutes. We ate well.’ All the time he was turning the knife over in his hands, examining it with what seemed to Li almost like fondness.
‘I thought it was the antlers that deer were killed for in the north-east. Some superstition about their powers of healing.’
The older man looked up. ‘It’s Sichuan you come from, isn’t it?’ Li nodded. ‘Pandas,’ said the Commissioner. ‘A protected species. You probably didn’t do much hunting in Sichuan.’
‘I’ve never much liked killing anything,’ Li said. ‘Even for the table.’