"How about his escape?" Sellitto said. "What's the deal where he changed into janitor clothes so fast."

"'Protean magic' it's called," Kara said. "Quick change. It's one of the things I've been studying for years. I just use it as part of my routines but there're some people, it's all they do. It can be amazing. I saw Arturo Brachetti a few years ago. He could do three or four dozen changes in one show—some of them in under three seconds."

"Three seconds?"

"Yeah. And see, true quick-change artists don't just change clothes. They're actors too. They walk differently, hold themselves differently, speak differently. He'll prepare everything ahead of time. The clothes are breakaway—they're held together with snaps or Velcro. Most of quick change is really quick strip. And they're made of silk or nylon, real thin, so we can wear layers of them. I sometimes wear five costumes under my top outfit."

"Silk?" Rhyme asked. "We found gray silk fibers," he explained. "The officers on the scene reported that the janitor was wearing a gray uniform. The fibers were abraded—sort of buffed to a matte finish."

Kara nodded. "So they'd look like cotton or linen, not shiny. We also use collapsible hats and suitcases, shoe coverings, telescoping umbrellas, all kinds of props that we hide on our bodies. Wigs, of course."

She continued, "To alter a face the most important thing is the eyebrows. Change those and the face is sixty, seventy percent different. Then add some prostheses—we call them 'appliances': latex strips and pads you put on with spirit gum. Quick-change performers study the basic facial structures of different races and genders. A good protean artist knows the proportions of a woman's face versus a man's and can change genders in seconds. We study psychological reactions to faces and posture—so we can become beautiful or ugly or scary or sympathetic or needy. Whatever."

The magic esoterica was interesting but Rhyme wanted specific suggestions. "Is there anything concrete you can tell us that'll help find him?"

She shook her head. "I can't think of anything that might lead you to a particular store or other place. But I do have some general thoughts."

"Go ahead."

"Well, the fact he used the changing rope and finger cups tells me he's familiar with sleight of hand. That means he'll be good at picking pockets, hiding guns or knives or things like that. Getting people's keys and IDs. He also knows quick change and it's obvious what kind of problem that'll be for you. But more important—the Vanished Man routine, the fuses and squibs, the disappearing ink, the black silk, the flash cotton means he's a classically trained illusionist."

She explained the difference between a sleight-of-hand artist and a true illusionist, whose acts involved people and large objects. "Why's that important for us?"

Kara nodded. "Because illusion is more than just physical technique. Illusionists study audience psychology and create whole routines to trick them—not just their eyes but their minds too. Their point isn't making you laugh because a quarter disappears; it's to make you believe in your heart that everything you see and believe is one way when in fact it's the opposite. There's one thing you'll have to keep in mind. Never forget it."