"And you're sure the writer wasn't faking?"
"Positive. There was a guard who saw ink going on paper, no question."
"Anything visible now?"
"Nothing."
Kincaid gave a grim laugh. "That's smart. So there was no record of the perp entering the building. And then somebody else wrote their name over the blank space and ruined whatever impression there might've been of his signature."
"Right."
"Anything on the sheet below the top one?"
Rhyme glanced at Cooper, who shone a bright light at an acute angle on the second sheet in the log--this, rather than covering the page with pencil lead, was the preferred method to raise impression evidence. He shook his head.
"Nothing," Rhyme told the document examiner. Then asked, "So how'd he pull that off?"
"He Ex-Laxed it," Kincaid announced.
"How's that?" Sellitto called.
"Used disappearing ink. We call it Ex-Laxing in the business. The old Ex-Lax contained phenolphthalein. Before it was banned by the FDA. You'd dissolve a pill in alcohol and make a blue ink. It had an alkaline pH. Then you'd write something. After a while, exposure to the air would make the blue disappear."
"Sure," said Rhyme, recalling his basic chemistry. "The carbon dioxide in the air turns the ink acidic and that neutralizes the color."
"Exactly. You don't see phenolphthalein much anymore. But you can do the same thing with thymolphthalein indicator and sodium hydroxide."
"Can you buy this stuff anyplace in particular?"
"Hm," Kincaid considered. "Well. . . . Just a minute, honey. Daddy's on the phone. . . . No, it's okay. All cakes look lopsided when they're in the oven. I'll be there soon. . . . Lincoln? What I was going to say was that it's a great idea in theory but when I was in the bureau there were never any perps or spies who actually used disappearing ink. It's more of a novelty, you know. Entertainers'd use it."
Entertainment, Rhyme thought grimly, looking at the board on which were taped the pictures of poor Svetlana Rasnikov. "Where would our doer find ink like that?"
"Most likely toy stores or magic shops."
Interesting . . .
"Okay, well, that's helpful, Parker."
"Come and visit sometime," Sachs called. "And bring the kids."
Rhyme grimaced at the invitation. He whispered to Sachs, "And why don't you invite all their friends too. The whole school . . ."
Laughing, she shushed him.
After he disconnected the call Rhyme said grumpily, "The more we learn, the less we know."
Bedding and Saul called in and reported that Svetlana seemed to be well liked at the music school and had no enemies there. Her part-time job wasn't likely to have produced any stalkers either; she led sing-alongs at kids' birthday parties.
A package arrived from the medical examiner's office. Inside was a p
lastic evidence bag containing the old handcuffs the victim had been restrained with. They were unopened, as Rhyme had ordered. He'd told the M.E. to compress the victim's hands to remove them since drilling out the locks could destroy valuable trace.
"Never seen anything like this," Cooper said, holding them up, "outside of a movie."
Rhyme agreed. They were antique, heavy and made of unevenly forged iron.
Cooper brushed and tapped all around the lock mechanisms but he found no significant trace. The fact they were antique, though, was encouraging because it would limit the sources they might've come from. Rhyme told Cooper to photograph the cuffs and print out pictures to show to dealers.