Broken Homes

his fingertips. ‘Are you sure you have the time for that?’ he asked.
    ‘Sussex and Surrey MCT will produce a weekly summary while the case is ongoing,’ I said. ‘It’ll take me ten minutes.’
    ‘I don’t think he takes me as seriously as he should,’ Nightingale told Dr Walid. ‘He still slopes off to conduct illicit experiments whenever he thinks I’m not looking.’ He looked at me. ‘What is your latest interest?’
    ‘I’ve been looking at how long various materials retain vestigia ,’ I said.
    ‘How do you measure the intensity of the vestigia ?’ asked Dr Walid.
    ‘He uses the dog,’ said Nightingale.
    ‘I put Toby in a box along with the material and then I measure the loudness and frequency of his barking,’ I said. ‘It’s no different from using a sniffer dog.’
    ‘How can you be sure of consistency of results?’ asked Dr Walid.
    ‘I ran a series of control experiments to eliminate variables,’ I said. Toby on his own in a box at nine a.m. and then at hourly intervals for the volume baseline. And then Toby in a box with various guaranteed inert materials for a baseline on that. The third day Toby hid under the table in Molly’s kitchen and had to be lured out with sausages.
    Dr Walid leaned forward as I talked – he at least appreciated a bit of empiricism. I explained that I’d exposed each material sample to identical amounts of magic, by conjuring a werelight – the simplest and most controllable spell I knew – and then put it in the box with Toby to see what happened.
    ‘Were there any significant findings?’ he asked.
    ‘Toby’s not very discriminating, so we’re talking a wide margin for error,’ I said. ‘But it was about what I expected. And in line with my reading. Stone retains vestigia the best, followed by concrete. The metals were all too similar to differentiate. Wood was next and the worst was flesh.’ In the form of a leg of pork which Toby subsequently ate before I could stop him.
    ‘The only surprise,’ I said, ‘were some of the plastics, which scored almost as high on the yap-o-meter as stone.’
    ‘Plastic?’ asked Nightingale. ‘That’s most unexpected. I’d always assumed that it was natural things that retained the uncanny.’
    ‘Can you email me the results?’ asked Dr Walid.
    ‘Sure.’
    ‘Have you considered testing other dogs?’ asked Dr Walid. ‘Perhaps different breeds would have different sensitivities.’
    ‘Abdul, please,’ said Nightingale. ‘Don’t give him any ideas.’
    ‘He is making progress in the art,’ said Dr Walid.
    ‘Barely,’ said Nightingale. ‘And I believe he’s replicating work that’s already been done.’
    ‘By who?’ I asked.
    Nightingale sipped his tea and smiled.
    ‘I’ll make a bargain with you, Peter,’ he said. ‘If you make better progress in your formal studies I shall tell you where to find the notes of the last brain-box who filled the lab with . . . Actually it was mostly rats, but I seem to remember a couple of dogs in his menagerie.’
    ‘How much better progress?’ I asked.
    ‘Better than you’re doing now,’ he said.
    ‘I wouldn’t mind seeing that data,’ said Dr Walid.
    ‘Then you should encourage Peter to study harder,’ said Nightingale.
    ‘He’s an evil man,’ I said.
    ‘And cunning,’ said Dr Walid.
    Nightingale eyed us placidly over the rim of his tea cup.
    ‘Evil and cunning,’ I said.
    The next morning I drove up to Hendon for part one of mandatory Officer Safety Training. You’re pretty much expected to do one of these courses every six months until Chief Inspector rank, but I doubt we’ll ever see Nightingale do one. We had a fun lecture on Excited Delirium, or what to do with people who are stoned out of their box. And then role-playing in the gym where we practised how to handle suspects without having them fall down the stairs. A couple of the officers had been at Hendon with me and Lesley, and we stuck together at lunch. They asked after Lesley and I gave them the official version, that she was physically assaulted during the riots in Covent Garden and that her attacker subsequently committed suicide before I could arrest him.
    In the afternoon we took it in turns to hide offensive weapons about our person while our colleagues searched us, a contest I won coming and going because I know how to hide a razor blade in the waist band of my jeans and I’m not afraid to go all the way up a suspect’s inner leg. Doing all the physical