‘Were those changed after the break-in?’

‘Of course. I changed everything I could think of, and in fact, the dial-in numbers have been changed again since. Plus we have callback modems. You call CAIN and he calls you back to make certain you’re legit.’ She looked discouraged and angry.

‘If you attached a virus to a program,’ I said, trying to help, ‘wouldn’t it change the size of the file? Couldn’t that be a way to find out where the virus is?’

‘Yes, it would change the file size,’ she said. ‘But the problem is that the UNIX program used to scan files for something like that is called checksum, and it’s not cryptographically secure. I’m sure who ever did this included a balancing checksum to cause the bytes in the virus program to disappear.’

‘So the virus is invisible.’

She nodded, distracted, and I knew she was thinking about Carrie. Then Lucy typed a who command to see what law enforcement agencies were logged on, if any. New York was. So were Charlotte and Richmond, and Lucy pointed out their modems to me. Lights danced across the front of them as data was transmitted over telephone lines.

‘We should go eat dinner,’ I said gently to my niece.

She typed more commands. ‘I’m not hungry now.’

‘Lucy, you can’t let this take over your life.’

‘You’re one to talk.’

She was right.

‘War has been declared,’ she added. ‘This is war.’

‘This is not Carrie,’ I said of the woman who, I suspected, had been more than Lucy’s friend.

‘It doesn’t matter who it is.’ She continued typing.

But it did. Carrie Grethen did not murder people and mutilate their bodies. Temple Gault did.

‘Was anything else of yours taken during the break-in?’ I tried again.

She stopped what she was doing and looked at me, her eyes glinting. ‘Yes, if you must know,’ she said. ‘I had a big manilla envelope that I didn’t want to leave in my dorm rooms at UVA or here because of roommates and other people in and out. It was personal. I thought it was safer in my desk up here.’

‘What was in this envelope?’

‘Letters, notes, different things. Some of them were from you, including the letter with the photograph and charge card. Most were from her.’ Her face colored. ‘There were a few notes from Grans.’

‘Letters from Carrie?’ I did not understand. ‘Why would she write you? Both of you were here at Quantico and you didn’t know each other before last fall.’

‘We sort of did,’ she said, her face turning a brighter red.

‘How?’ I asked, baffled.

‘We met through a computer bulletin board, through Prodigy over the summer. I saved all the printouts of the notes we sent.’

‘Did you deliberately try to arrange it so you could be at ERF together?’ I said as my disbelief grew.