We entered a gray rabbit warren of cubicles with workstations and printers and stacks of paper. CAIN himself was behind glass in an air-conditioned space filled with monitors, modems and miles of cable hidden beneath a raised floor.

‘I’ve got to check something,’ she said, scanning her fingerprint to unlock CAIN’s door.

I followed her into chilled air tense with the static of invisible traffic moving at incredible speeds. Modem lights blinked red and green, and an eighteen-inch video display announced CAIN in bold bright letters that looped and whorled like the fingerprint of the person who was just scanned in.

‘The photograph was in the envelope with the American Express card he apparently now has,’ I said. ‘Logic would tell you that he may have both.’

‘Someone else could have it.’ She was intensely watching the modems, then glancing at the time on her screen and making notes. ‘It depends on who actually went through my desk.’

We had always assumed it was Carrie alone who had broken in and taken whatever she wanted. Now I was not so sure.

‘Carrie may not have been by herself,’ I said.

Lucy did not reply.

‘In fact, I don’t believe Gault could have resisted the opportunity to come in here. I think he was with her.’

‘That’s awfully risky when you’re wanted for murder.’

‘Lucy, it’s awfully risky to break into here to begin with.’

She continued making notes while CAIN’s colors swirled on the screen and lights glowed on and off. CAIN was a space-age squid with tentacles connecting law enforcement entities here and abroad, his head an upright beige box with various buttons and slots. As cold air whirred, I almost wondered if he knew what we were saying.

‘What else might have disappeared from your office?’ I then said. ‘Is there anything else missing?’

She was studying a modem’s flashing light, her face perplexed. She glanced up at me. ‘It’s got to be coming in through one of these modems.’

‘What is?’ I asked, puzzled.

She sat before a keyboard, struck the space bar and the CAIN screen saver vanished. She logged on and began typing UNIX commands that made no sense to me. Next she pulled up the System Administrator Menu and got into the audit log.

‘I’ve been coming in here routinely and checking the traffic on the modems,’ she said, scanning. ‘Unless this person is physically located in this building and hardwired into the system, he’s got to be dialing in by modem.’

‘There’s no other way,’ I said.

‘Well’ - she took a deep breath - ‘theoretically you could use a receiver to pick up keyboard input via Van Eck radiation. Some Soviet agents were doing that not so long ago.’

‘But that wouldn’t actually get you inside the system,’ I said.

‘It could get you passwords and other information that might get you in if you had the dial-in number.’