He began advancing the film, speeding past scene after scene of the empty bedroom, until suddenly a figure was there. Marino rewound and the figure quickly walked backward out of the room.

Marino said, 'Look what happens exactly an hour and eleven minutes later.' He hit the play button again.

Carrie Grethen walked into the bedroom, dressed like Gault. Were it not for her white hair, I might have thought she was him.

'What? She's got on his suit?' Tucker asked, amazed.

'Not his suit,' I said. 'She's got on one like it, but it's not the suit Gault was wearing.'

'How can you tell?' Tucker said.

'There's a handkerchief in the pocket. She took Gault's handkerchief to wipe blood off him. And if you go back you'll see his jacket had no flaps on the pockets, but hers does.'

'Yeah,' Marino said. 'That's right.'

Carrie looked around the room, on the floor, on the bed, as if she had lost something. She was agitated and angry, and I was certain she was on the wrong side of a cocaine high. She looked around a minute longer, then left.

'I wonder what that was about,' Tucker said.

'Hold on,' Marino told us.

He advanced the film and Carrie was back. She searched some more, scowling, pulling covers back from the bed and looking under the bloody pillow. She got down on the floor and looked under the bed. She spewed a stream of profanities, eyes casting about.

'Hurry up,' Gault's impatient voice sounded from somewhere beyond the room.

She looked in the dresser mirror and smoothed her hair. For an instant, she was staring straight into the camera at close range, and I was startled by her deterioration. I once had thought her beautiful, with her clean complexion, perfect features and long brown hair. The creature standing before us now was gaunt and glassy eyed, with harsh white hair. She buttoned the suit jacket and walked off.

'What do you make of that?' Tucker asked Marino.

'I don't know. I've looked at it a dozen times and can't figure it out.'

'She's misplaced something,' Wesley said. 'That seems obvious.'

'Maybe it was just a last check,' Marino said. 'To make certain nothing was overlooked.'

'Like a video camera,' Tucker wryly said.

'She didn't care if something was overlooked,' Wesley said. 'She left Gault's bloody handkerchief on the floor.'

'But both of them was wearing gloves,' Marino said. 'I'd say they were pretty careful.'

'Was any money stolen from the house?' Wesley asked.

Marino said, 'We don't know how much. But Brown's wallet was cleaned out. He was probably missing guns, drugs, cash.'

'Wait a minute,' I said. 'The envelope.'

'What envelope?' Tucker asked.

'They didn't put it in his pocket. We watched them dress him and zip him up inside the pouch, but no envelope. Rewind it,' I said. 'Go back to that part to make certain I'm right.'

Marino rewound the tape and replayed the footage of Carrie and Gault moving the body out of the room. Brown was definitely zipped inside the pouch without the pink note that I had found in the breast pocket of his pajamas. I thought of other notes I had gotten and of all the problems Lucy was having with CAIN. The envelope had been addressed to me and fixed with a stamp as if the author's intention were to mail it.

'That may be what Carrie couldn't find,' I said. 'Maybe she's been the one sending me the letters. She intended to mail this most recent one, too, explaining why it was addressed and stamped. Then, unbeknownst to her, Gault put it in Brown's pajama pocket.'

Wesley asked, 'Why would Gault do that?'

'Perhaps because he knew the effect it would have,' I replied. 'I would see it in the morgue and instantly know that Brown was murdered and Gault was involved.'

'But what you're saying is that Gault isn't CAIN. You're saying that Carrie Grethen is,' Marino said.

It was Lucy who spoke. 'Neither of them is CAIN. They are spies.'

We were silent for a moment.

'Obviously,' I said, 'Carrie has continued helping Gault with the FBI computer. They are a team. But I think he took the note she wrote to me and did not tell her. I think that's what she was looking for.'

'Why would she look for it in Brown's bedroom?' Tucker wondered. 'Is there a reason she might have had it in there?'

'Certainly,' I said. 'She took her clothes off in there. Perhaps it was in a pocket. Play that part, Marino. When Gault is moving the dark clothing off the bed.'

He went back to that segment, and though we could not specifically see Gault remove the letter from a pocket, he did tamper with Carrie's clothing. He certainly could have gotten her letter at that time. He could have placed it in Brown's pocket later, in the back of the van or perhaps in the morgue.

'So you're really thinking she's the one who's been sending the notes to you?' Marino asked skeptically.

'I think it's probable.'

'But why?' Tucker was confounded. 'Why would she do this to you, Dr. Scarpetta? Do you know her?'

'I do not,' I said. 'I've only met her, but our last encounter was quite confrontational. And the notes don't seem like something Gault would do. They never have.'

'She would like to destroy you,' Wesley calmly said. 'She would like to destroy both Lucy and you.'

'Why?' Janet asked.

'Because Carrie Grethen is a psychopath,' Wesley said. 'She and Gault are twins. It's interesting that they are now dressing alike. They look alike.'

'I don't understand what he did with the letter,' Tucker said. 'Why not just ask Carrie for it instead of taking it without telling her?'

'You're asking me to tell you how Gault's mind works,' Wesley said.

'Indeed I am.'

'I don't know why.'

'But it must mean something.'

'It does,' Wesley said.

'What?' Tucker asked.

'It means she thinks she has a relationship with him. She thinks she can trust him, and she's wrong. It means he will eventually kill her, if he can,' Wesley said as Marino turned on lights.

Everybody squinted. I looked at Lucy, who had nothing to say, and sensed her anguish in one small way. She had put her glasses on when she did not need them to see unless she was sitting at a computer.

'Obviously, they're working tag team,' Marino said.

Janet spoke again. 'Who's in charge?'

'Gault is,' Marino said. 'That's why he's the one with the gun and she's the one giving the blow job.'

Tucker pushed back his chair. 'They somehow met Brown. They didn't just show up at his house.'

'Would he have recognized Gault?' Lucy asked.

'Maybe not,' Wesley said.

'I'm thinking they got in touch with him - or she did, anyway - to get drugs.'

'His phone number is unpublished but not unlisted,' I said.

'There weren't any significant messages on his answering machine,' Marino added.

'Well, I want to know the link,' Tucker said. 'How did these two know him?'

'Drugs would be my guess,' Wesley said. 'It may also be that Gault got interested in the sheriff because of Dr. Scarpetta. Brown shot someone Christmas Eve, and the media covered it ad infinitum. It was no secret that Dr. Scarpetta was there and would end up testifying. In fact, she might have ended up in the jury pool since, ironically, Brown summoned her for jury duty.'

I thought of what Anna Zenner said about Gault bringing gifts to me.

'And Gault would have been aware of all this,' Tucker said.

Wesley said, 'Possibly. If we ever find where he lives, we may discover that he gets the Richmond newspaper by mail.'

Tucker thought for a while and looked at me. 'Then who killed the officer in New York? Was it this woman with white hair?'

'No,' I said. 'She could not have kicked him like that. Unless she is a black belt in karate.'

'And were they working together that night in the tunnel?' Tucker asked.

'I don't know that she was there,' I said.

'Well, you were there.'

'I was,' I said. 'I saw one person.'

'A person with white hair or red hair?'

I thought of the figure illuminated in the arch. I remembered the long dark coat and pale face. I had not been able to see the hair.

'I suspect it was Gault down there that night,' I said. 'I can't prove it. But there is nothing to suggest that he had an accomplice when Jane was killed.'

'Jane?' Tucker asked.

Marino said, 'That's what we call the lady he killed in Central Park.'

Then the implication is he did not form a violent partnership with this Carrie Grethen until he returned to Virginia, after New York.' Tucker continued trying to fit the pieces together.

'We really don't know,' Wesley said. 'It's never going to be an exact science, Paul. Especially when we're dealing with violent offenders rotting their brains with drugs. The more they decompensate, the more bizarre the behavior.'

The chief of police leaned forward, looking hard at him. 'Please tell me what the hell you make of all this.'

'They were connected before. I suspect they met through a spy shop in northern Virginia,' Wesley said. 'That is how CAIN was compromised - is compromised. Now it appears the connection has moved to a different level.'

'Yeah,' Marino said. 'Bonnie's found Clyde.'