“I don’t see anything. If it broke in here, I don’t see the rest of it. I guess it could still be attached to the tooth. I broke a crown once and part of it was still stuck to the little nub that’s left of my tooth.” Becky looks past Scarpetta, at the copper tub. “Talk about the biggest false-positive on the planet,” she adds. “This will be a new one for the books. One of the few times I need to use luminal, and the damn tub and sink are copper. Well, we can forget it.”

“I don’t use luminol anymore,” Scarpetta says, as if the oxidizing agent is a disloyal friend.

Until recently, it was a forensic staple and she never questioned using it to find blood no longer visible. If blood had been washed away or even painted over, the way to know was to mix up a spray bottle of luminol and see what fluoresced. The problems have always been many. Like a dog that wags its tail at all the neighbors, luminol is excited by more than the hemoglobin in blood and is, unfortunately, quite responsive to a number of things: paint, varnish, Drano, bleach, dandelions, thistle, creeping myrtle, corn. And, of course, copper.

Lucy retrieves a small container of Hemastix for a presumptive test, looking for any residue of what may be scrubbed-away blood. The presumptive test says blood might be there, and Scarpetta opens the box of Bluestar Magnum and removes a brown glass bottle and a foil pack, and a spray bottle.

“Stronger, longer-lasting, don’t have to use it in total darkness,” she explains to Becky. “No sodium perborate tetrahydrate, so it’s nontoxic. Can use it on copper because the reaction will be a different intensity, a different color spectrum, and will have a different duration than blood.”

She has yet to see blood inside the master bathroom. Despite what Madelisa claimed, the most intense white light revealed not the slightest stain. But this is no longer surprising. By all indications so far, after she fled from the house, the killer meticulously cleaned up after himself. Scarpetta selects the finest setting on the spray bottle’s nozzle and pours in four ounces of sterile water. To this she adds two tablets. She gently stirs with a pipette for several minutes, then opens the brown glass bottle and pours in a sodium hydroxide solution.

She begins to spray, and spots and streaks and shapes and spatters luminesce bright cobalt blue all over the room. Becky takes photographs. A little later, when Scarpetta has finished cleaning up after herself and is repacking her crime scene case, her cell phone rings. It’s the fingerprint examiner from Lucy’s labs.

“You’re not going to believe this,” he says.

“Don’t ever start a conversation like that with me unless you mean it.” Scarpetta isn’t joking.