“Sheriff's scientific guess. He tuned it down from the kid's voice using a preset frequency.”

“How can he be sure the kid's voice was altered in the first place?”

“Because his machines told him so. He came across it by accident—working on the screams—which, incidentally, he's ninety-nine percent positive are Hewitt's. Then he got to the kid chanting and something bothered him about it—the evenness of the voice.”

“The robot quality,” I said.

“Yeah. But he didn't assume brainwashing or anything else psychological. He's a techno-dude, so he analyzed the sound waves and saw something fishy with the cycle-to-cycle amplitude—the changes in pitch within each sound wave. Real human voices shimmer and jitter. This didn't, so he knew the tape had been messed with electronically, probably using a pitch shifter. It's a gizmo that samples a sound and changes the frequency. Tune up, you've got Alvin and the Chipmunks; tune down, you're James Earl Jones.”

“Hi-tech bad guy,” I said.

“Not really. The basic machines are pretty cheap. People attach them to phones—women living alone wanting to sound like Joe Testosterone. They're also used for recording music—creating automatic harmonies. A singer lays down a vocal track, then creates a harmony and overdubs it, instant Everly Brothers.”

“Sure,” said Robin. “Shifters are used all the time. I've seen them interfaced with amps so guitarists can do multiple tracks.”

“Lyle Gritz,” I said. “The next Elvis. . . . How'd the sheriff know which frequency to tune down to?”

“He assumed we were dealing with a male bad guy using a relatively cheap shifter because nowadays the better machines can be programmed to include jitter. The cheap ones usually come with two, maybe three standard settings: tune up to kid, tune down to adult, sometimes there's an intermediate setting for adult female. By computing the pitch difference, he worked backwards and tuned down. But if our guy's some sort of acoustics nut with fancy equipment, there may be other things he's done to alter his voice and what you heard may be nowhere near his real voice.”

“It may not even be his voice that he altered. He could have shifted someone else's.”

“That, too. But you think you might have heard him before.”

“That was my first impression. But I don't know. I don't trust my judgment anymore.”

“Well,” he said, “at least we know there's no actual kid involved.”

“Thank God for that. Okay, leave the tape with me. I'll work with it tomorrow, see if anything clicks.”

“The screams being Hewitt, what does “ninety-nine percent' mean?”

“It means the sheriff'll get up on the stand and testify it's highly probable to the best of his professional knowledge. Only trouble is, we need to get someone on trial first.”

“So I was right, this isn't some homeless guy. He'd need a place to keep his equipment.”