Rock Doc

As a kid, I read the Sherlock Holmes stories and the mysteries of Agatha Christie. As an adult, I wrote four mysteries that focused on a Quaker heroine solving crimes she happened across in her religious community. (I published them using my grandmother’s name, Irene Allen, as a pseudonym.) And, as a geologist, I’ve read about real-life criminal investigations that involved samples of sand and soil.

But it wasn’t until I talked with Dr. Nathalie Wall of the chemistry department at Washington State University that I got my head around forensic science that relates to radioactive materials.

“The...