“Do you mean that Katrina Grooten worked with arsenic here at the Cloisters?”

Bellinger fidgeted now, swiveling in his chair as though he were looking for something north of the heavy traffic crawling across the George Washington Bridge.

“No, no, I can’t say that she did.”

“But a lot of the other staff members do?” Chapman asked.

He thought before answering. “I wouldn’t say very many. Four at the most. Those who work under my direct supervision. They’ll all tell youI’m the one who uses it most.”

“Why? In what form?”

“My particular scholarship is in the field of illustrated manuscripts.” He stood up and walked to some of the open volumes that had been moved to accommodate our gathering. “From the earliest monastic houses on, the production of books was an essential task the monks performed for the greater ecclesiastical community. Each of them had what was called a scriptorium, where scribes and illuminators copied classical texts. Here, in the building we call the Treasury, we’ve got a unique collection of these exquisite books.”

Bellinger picked one up and carried it back to us. “Certainly our most prized possession. Perhaps you know it. TheBelles Heures. ”

“Only from the museum catalog.”

“This one was described in the inventory of the Duke of Berry in 1413. These were made by the monks for the rich patrons and royal families, who were supposed to say their prayers at the same canonical hours that were observed in the monasteries-book of hours.”

The two pages he displayed were ornately decorated in gold leaf around the text of the prayers. There were stunning paintings in vibrant colors, and I studied the heavy pages before moving out of the way for Mike and Mercer.

“How has this survived in such good condition?” I asked.

“The books always suffered less damage than things like tapestries. They couldn’t be melted down into bullion, like jewelry or pieces of gold, so thieves and rogues didn’t perceive them to have very much value. It’s just that their colors fade over time, and we restore them here. That’s the work I like to do.”

“And the materials?”

“We try to imitate what was done in medieval times.” Bellinger pointed at parts of the elegant page. “Powdered gold for these elaborate drawings was made by grinding the actual metal with honey and mixing it with egg whites. Black came from a carbon-based ink. They made blue in a number of ways. The most expensive was actually ground from lapis lazuli, or indigo mixed with white lead-which is actually quite poisonous itself. And yellow, that’s where the orpiment comes in. The monks used saffron to produce a yellow pigment in the early days. But it wasn’t permanent.”

“What’s orpiment?”

“It’s an arsenic compound, Detective. Very widely used to give us a fine yellow color. You can see how effective it is right on that page you’re examining now. In our workshop downstairs, we’ve got more than enough to make someone quite ill.”

“Is it secured?”

“Do we keep it under lock and key? Of course not. Our little restoration area doesn’t get a lot of outside interest. It’s very intense labor and doesn’t excite much of the general public.”

“Did Ms. Grooten have access to the room?”

Bellinger paused for a moment. “Certainly. But she wasn’t in the habit of licking paintbrushes, Mr. Chapman.” He was beginning to snap at Mike.

“And Napoléon didn’t chew on his wallpaper, either.”

“What?” the puzzled curator asked.

“There was arsenic found in locks of Napoléon’s hair. Lots of it. There were theories that his captors did him in, and some wild conjecture that he was poisoned by the vapors from the wallpaper color in his room at St. Helena’s, during his exile. Copper arsenite.”

“Scheele’s green, probably. A brilliant pigment. We’ve got some of that, too. Don’t use as much of it because it wasn’t created until after the Renaissance, so it wouldn’t be authentic to our pieces.”

“That’s exactly why we need to know what Grooten was working on and who she dealt with,” I said. Mike knew more about the great Corsican general than Pat McKinney knew about the law. If he got off on a Napoléonic tangent, we’d be here until midnight. “I assume you have a way to tell us whether any tubes or vials are missing?”

“I’m sure I don’t. The workmen get all the supplies they need by ordering from the Met. Ask Pierre Thibodaux. Ask Erik Poste. Ask the other medievalists.”

His counterparts at the main branch were obvious interview subjects. “Why Thibodaux? Why Poste?”

“I’m sure the director’s office has all the billing records for the goods that are purchased for our needs. The ever-rigid Ms. Drexler must be able to put her fingers on that. There are a host of toxic substances in paints and pigments, varnishes and cleaning agents. And we’re not the only ones who restore old artworks, Ms. Cooper. Mr. Poste’s European collection has far more extensive restoration projects than do I.”

I didn’t think he was pointing the finger at other colleagues as much as he was highlighting how frustrating our search would be in an institution that apparently needed poisons to enliven the glorious holdings the public came to view.

“May we have this copy of Ms. Grooten’s personnel file to take with us?” I asked.

“I’ve reproduced the entire thing for you.”

I opened it from the back and saw the letter of resignation first. It had been written on a word processor and dated December 24 of the previous year. In place of a signature was the capital letterK, drawn with a marker in almost a stick-figure print.

“Is that how she usually signed things, not spelling out her whole name?”

Bellinger took the document from my hand. “Straight and simple, just like that. She usually used both initials, but herG was more Gothic, if you will.” He closed his eyes as if to call up an image of her signature. “TheG would have been harder to imitate, come to think of it, if someone else did the writing.”

I hadn’t suggested that the letter wasn’t written by Grooten. “Why would you think she didn’t write this herself?”

“I-uh, I don’t know. When did she die? I just mean she never came back to work after the twentieth, if I’m not wrong. Maybe she’d already been murdered, and the killer wrote this so I wouldn’t be worried about her disappearance.”

“And were you?”

“I was out of town that entire period, visiting my in-laws for the holidays. I never knew Katrina had quit until I returned in January. She was gone, and I thought she had left the country. There wasn’t much I could do about it until she sent me a forwarding address, as that letter said she would do once she got set up at home.”

“Did she have a computer when she was working here?”

“Yes, of course.”

“With an e-mail address?” I could see where Mike was going.

“So far as I know, the only e-mail address Katrina had was through the museum system. You’ll see in her file some correspondence that arrived for her after she left for South-” He caught himself. “After she resigned. We bought an entire new computer system, hardware and software, which was installed after the first of the year.

“When they dismantled Katrina’s equipment, I authorized the head of our management information systems to go into her account with her password, to make sure that nothing had come in for her that was related to museum business.”

“Did they find anything?”

“Minor correspondence, really. There were a few responses to requests for materials from museums overseas. We’ve got a good number of objects out on loan that she wanted to see photographs of, for their possible inclusion in the bestiary show. I forwarded those to the committee she had been working with. Gaylord, Friedrichs, Poste, and the others.”

“Anything personal?”

“Those should be in that packet you’re holding. A bunch of Christmas and New Year’s greetings from people she knew, here and abroad.”