I pushed the button, and felt the spring-loaded apparatus nudge the top of the frame upward. Enough wood was now available that I could get a handhold and pull.

The frame was too large and heavy for me to extract standing up, so I laid the painting on the carpet and pulled it out that way. “Oh, my God,” I whispered as the Cezanne came into view. The cobalt blue and muted shades of orange and green were indescribably breathtaking. I shook my head, dazed.

I heard a scuffing sound, realized that Officer O’Hara could enter at any moment, and rushed to lay the other Tavernier down on the rug. I pushed the button releasing the hidden drawer and slid the Matisse out of its secret place. It was gorgeous, the perspective complex, and the colors vivid.

Both canvases lay flat against plywood backing, clamped at the top to hold them in place. I was easily able to release them, lift them out, and roll them up. Sliding the three-sided structures back in place, I left the paintings leaning against the wall.

As I passed through the hall, I was relieved to see O’Hara perched against a porch column, staring at the ocean, smoking a cigarette. I headed for the basement, cradling the two rolled paintings. I shivered a little as I entered the cooler, darker environment, whether from the chill of the cellar, the memory of yesterday’s panic attack, or the thrill of my discovery, I couldn’t tell.

I tenderly placed the paintings on the top of the leather truck, and squatted down to open the hard-to-find bottom drawer. It slid out smoothly, and unrolling the paintings, I laid them one on top of the other in the oversized space, closed the drawer, and ensured that the two handles were snuggled into their openings.

Standing, I realized that I’d been hyperventilating, and I forced myself to take several slow, calming breaths. I wasn’t out of the woods yet. I grabbed the three-sided frame from the workbench and held it upside down. Under the targeted beam of my flashlight, I could see the small spring. From the top, when nuzzled in place, it was essentially invisible. I carried it upstairs, inserted it into the opening in the third painting’s frame, and pushed it home.

I was done, and I sat down on the floor to catch my breath. “Whew,” I said aloud.

When I’d first examined Mr. Grant’s treasures, all three Tavernier frames were intact. I wondered what the police had thought when they’d looked at the gap. Probably nothing more than that a piece of a frame had broken off.

Last night, with sleep eluding me, I concluded that Mr. Grant had intended to destroy all three of the fabricated frames as soon as the stolen paintings had been sold, thus eliminating evidence of his deception. He’d taken the Renoir from its hiding place, and since he never intended that it would return to its home behind the Tavernier, he’d brought the three-sided frame to his workroom to demolish. No doubt he’d eventually expected to reframe the Taverniers, and I was willing to bet that somewhere, in the back of a closet, or in the attic, for instance, we’d find three traditional gilt frames ready to go.

I stood up, took a deep breath, and rehung all three paintings. It was exhausting.

I allowed myself a private grin and an “atta girl.” I brushed hair out of my eyes, excited that I’d discovered the missing paintings, and proud that I’d found a way to keep them safe.

But my pride was mitigated by icy fear. Another thought I’d had last night, as I’d struggled to sleep, was that maybe someone had killed Mr. Grant in order to have unfettered access to the Cezanne and the Matisse.

If Mr. Grant hadn’t liked how the negotiations over the Renoir had gone, and had decided not to proceed, killing him had been the only way of getting the art. Or maybe, I thought, Mr. Grant was killed not because he’d withdrawn his offer to sell the Renoir but because his death allowed the killer to avoid receiving only a small percentage of the proceeds of its sale. With Mr. Grant out of the way, the murderer could take it all. But only if he-or she-could locate the missing paintings.

It seemed obvious to me that the Renoir had been stolen at the same time that the murder occurred. What a disappointment it must have been for the murderer to realize that everyone seemed to know that the Renoir existed. Too risky to keep, and too risky to sell, it must have seemed clever to the killer to plant it at my warehouse in order to try to frame me for Mr. Grant’s murder.

I shook my head, sickened at the thought that someone could do such a thing to me. Whoever it was, I could imagine their growing frustration. The Renoir might be off limits, but if Mr. Grant had mentioned the other paintings, perhaps dangling them as a carrot during the negotiations, and if the killer hadn’t known that Mrs. Grant’s ledger would reveal the paintings’ existence to the police, the murderer might think he-or she-was sitting pretty.

Of course, a search couldn’t be undertaken while the house was under police custody as a crime scene, but as soon as the authorities unsealed it, someone had entered and had, apparently, started to hunt for the paintings while I was in the basement.

My final conclusion, and I shivered with fear at the thought, was that if someone had murdered once to acquire priceless masterpieces, that person wouldn’t hesitate to kill again.

It was almost 6:30 when I got to my office. I ran inside, punched the code to turn off the alarm, and dashed upstairs to my office.

The best way to establish protocols is to actually do research. Otherwise, your decisions are based only on theory and can be arbitrary. Still, research only isn’t enough. Setting reasonable price ranges requires knowledge, intuition, and street smarts. You have to consider factors such as the condition of the piece relative to other examples that have sold, current market demand compared to what economic conditions existed when other similar pieces were auctioned, and unique factors such as a distinctive provenance-and determine which ones matter most.

Two of my office walls were stocked with various guidebooks and auction catalogues. In addition, we subscribed to several Web sites that tracked and reported auction results worldwide.

As a test case, I selected the now-silent Queen Anne grandfather clock standing in Mr. Grant’s hallway. I wanted to see how long it took me to set a price. It was a reasonable test selection, since it was representative of the bulk of the items in the Grant estate: valuable, but not unique.

Noting my starting time, I quickly sorted through the American furniture catalogues that filled about a quarter of my bookshelves and found two clocks that were similar to Mr. Grant’s. One had been sold by a Florida dealer, Shaw’s Antiques, in 2003. Mark Shaw described it as “magnificent.” Barney’s firm, Troudeaux’s New Hampshire Auctions, had auctioned the second in 2002. M. Turner described the clock’s condition as “very good.” Which meant it wasn’t “magnificent.”

Most antique dealers used “excellent” or “mint” to indicate pristine condition, but some were more poetic, and used terms like “magnificent.” The bottom line was that there was no standardization in the industry, so it was important for buyers to know how a dealer used words. “Magnificent” implied perfection. “Very good” usually meant there was some minor or normal wear.

Shaw’s had estimated that the clock would sell for $9,000 and it had actually sold for $10,300. Troudeaux’s had expected the clock to bring in $10,500, so its sales price of $6,750 must have been a huge disappointment. That was quite a spread-the Florida clock fetched $3,550 more than the one Barney sold.

Big differentials in prices between two similar items usually reflected differences in quality-which was, I knew from experience, impossible to define precisely. In this case, however, it seemed obvious why Shaw’s clock did so much better. First, it was in better condition than the one Barney sold. Second, according to Shaw’s description, the clock had been owned by a former governor of Georgia. That kind of connection often led to higher prices. Prestige by association. Besides which, Barney’s estimate might reflect wishful thinking or whimsy. His firm’s research was always suspect; whether from indifference or sloppiness, his estimates were wrong more often than they were right.