Doubting that God had deputized Harry Frost, Isaac Bell took a chance on Di Vecchio’s mental state. “But you tried to kill him, didn’t you?”

“And failed,” she answered. She looked Bell in the face. “I have had months to think about it. I believe that a part of my soul held back. I don’t remember everything that happened that day, but I do recall that when the knife missed his neck it carved a long cut in his arm. Here . . .” She ran her fingers in an electric glide down the inside of Bell’s forearm.

“I was glad. But I can’t remember whether I was glad because I drew blood or glad because I didn’t kill.”

“What did Marco steal?”

“My father’s work.”

“What work was that?”

“My father was aeroplano cervellone—how do you say?—brain. Genius!”

“Your father invented flying machines?”

“Yes! Bella monoplano. He named it Aquila. Aquila means ‘eagle’ in American. When he brought his Aquila to America, he was so proud to immigrate to your country that he named her American Eagle.”

She began talking a mile a minute. Marco Celere had worked for her father in Italy as a mechanician, helping him build the aeroplanes he invented. “Back in Italy. Before he made his name short.”

“Marco changed his name? What was it?”

“Prestogiacomo.”

“Prestogiacomo,” Bell imitated the sound that rolled off her tongue. He asked her to spell it and wrote it in his notebook.

“When Marco came here, he said it was too long for Americans. But that was a lie. Everyone knew Prestogiacomo was ladro. Here, his new name, Celere, only means ‘quick.’ No one knew the kind of man he really was.”

“What did he steal from your father?”

What Marco Celere had stolen, Di Vecchio claimed, were new methods of wing strengthening and roll control.

“Can you explain what you mean by roll control?” Bell asked, still testing her lucidity.

She gestured, using her long graceful arms like wings. “When the aeroplano tilts this way, the conduttore—pilota—changes the shape of wing to make it tilt that way so to be straight.”

Recalling his first conversation with Josephine, Bell asked, “Did your father happen to invent alettoni?”

“Yes! Si! Si! That’s what I am telling you. Alettoni.”

“Little wings.”

“My father,” she said, tapping her chest proudly, “my wonderful babbo. Instead of warping the whole wing, he moved only small parts of it. Much better.”

Bell passed his notepad to her and handed over his Waterman fountain pen. “Can you show me?”

She sketched a monoplane, and depicted the movable hinged parts at the back of the outer edges of the wings. It looked very much like the yellow machine that Josephine was flying.

“Alettoni—hinged little wings—is what Marco stole from your father?”

“Not only. He stole strength, too.”

“I don’t understand.”

“My father learned how wings act to make them strong.”