Monday Mourning

“The jury found Monsieur Pétit guilty on all counts.”

“When?”

“Yesterday.”

“That was fast.”

“When she called, the crown prosecutor said she was certain your testimony was instrumental.” LaManche looked at the papers in my hand. “But that is obviously not why you are here.”

“I have the Carbon 14 results.”

“That, too, was fast.” Surprised.

“This lab is very efficient.” I didn’t mention the additional fee.

LaManche rose and joined me at the small oval table beside his desk. I spread the printout and we both bent over it.

"“Two variables matter,” I began. “The radioactivity of a known standard, and the radioactivity of our unknown sample. We’ve already discussed the phenomenon of atmospheric nuclear testing and its effect on Carbon 14 levels, so, to simplify, just assume that the standard value for Carbon 14 in 1950 is one hundred percent. Any value over that represents ‘bomb,’ or modern carbon, and indicates a death date more recent than 1950.”

I pointed to the last figure in a column labeled “Measured Radiocarbon Age.

“The pMC for LSJML-38428 is 120.5, plus or minus .5.”

“A percent modern carbon significantly higher than one hundred percent.”

“Yes.”

“Meaning this girl died since 1950?”

“Yes.”

“How long after 1950?”

“It’s tricky. By the time atmospheric testing was banned in 1963, pMC values had elevated to one hundred ninety percent. But what goes up must come down. So a pMC value of one hundred twenty percent could indicate a point on the upside of the curve, when levels were increasing, or a point on the downside, when levels were dropping.

“Meaning?”

“Death could have occurred in the late fifties or in the mid to late eighties.”

LaManche’s face sagged visibly.

“It gets worse. The present pMC value is around one hundred seven percent.” I pointed to the figures for LSJML-38426 and LSJML-38427.

“Mon Dieu.”

“These girls died as long ago as the early fifties, or as recently as the early nineties.

“You will inform Monsieur Claudel of these results?”

“Oh yes,” I said. With feeling.

LaManche steepled his fingers, tapped them against his lower lip.

“If these girls disappeared during the past twenty years, it is possible they will be in the system. Descriptors must be sent to CPIC.”

LaManche referred to the Canadian Police Information Centre, the equivalent of NCIC, the National Crime Information Center in the United States.