He waded through about four paragraphs and looked up at her, eyebrows arching a question. She smiled and opened her purse, a large black leather thing. He half-expected her to take out a gun, but she took out a ball of blue yarn and two knitting needles and a pebbly length of scarf-in-progress.

“Pretend you’re in Catholic school, Mr. Grady. What is present in the clothing?”

“Um … traces of salt, an alcohol-based mixture that the lab identified as Old Spice cologne, tobacco residue—the preacher liked his cigarettes and—what the hell is this?”

“Benzine and toluene. Dry cleaning compounds.”

“Oh.” Martin continued down the list. “Benzoic acid—”

“A distillate of benzine. Not a very good dry cleaners; all those chemicals are present in far greater concentrations than they should be.” Mrs. Womack counted a row of stitches and started clacking, a dry quiet sound that reminded him of dice. “Go on.”

“Sulphur dioxide—”

“Commonly used as a disinfectant and preservative.”

“Sulfonmethane.”

“A hypnotic agent.”

“Hydrochloric and hydrocyanic acids.”

“Also used as clarifying agents in dry cleaning.”

Grady watched as Mrs. Womack calmly knitted an entire row.

“Are you trying to tell me,” he said slowly, “that somebody killed him with dry cleaning fluids? That these chemicals combined will burn?”

“Not at all.” She started a second row. “But it might interest you to know that Burt Marshall—who died right here in Dallas, Texas—was half-owner of a dry cleaners. And that earlier last year he applied for a patent for a new dry cleaning solution, but withdrew the request within three weeks. Isn’t that interesting?”

“But if these chemicals don’t burn—”

“By themselves.” She inspected the row and adjusted it with nudges of her fingers. “Do you think you love Adrian?”

“Pardon me?” He blinked and sat upright. He had to look down to be sure Carling wasn’t awake. “What?”

“Do you think you’re in love with her?”

He opened his mouth to say no, shut it, and tried again. “I don’t know.”

“Well, I do. Let me give you a piece of advice, son. I love Adrian like she’s my own, but I’d never let a boy of mine marry her.” She smiled wolfishly. “She’s too much for you.”

“What makes them burn?”

Mrs. Womack looked over at Agent Mendoza, who sat impassive and still in his chair. Without any visible signal, he stood up and left the room.

“Body heat,” she said, and went back to her knitting. “Most of the early chemicals used for dry cleaning were unstable and flammable, you know—boiling points of as low as ninety degrees. Up to the turn of the century, they were still using kerosene and gasoline to fume clothes. I think our Mr. Marshall stumbled onto what he thought was a new dry cleaning process—but it turned out to have a low boiling threshhold. And once it’s combined with salt from sweat—”