To ensure they got the right items, the specialists from Idaho brought radiation detectors and small samples of dangerous materials to calibrate them: specifically, a plastic-covered disk of plutonium, a material that can be used to fuel nuclear weapons, and another of cesium, a highly radioactive isotope that could potentially be used in a so-called “dirty” radioactive bomb.

But when they stopped at a Marriott hotel just off Highway 410, in a high-crime neighborhood filled with temp agencies and ranch homes, they left those sensors on the back seat of their rented Ford Expedition. When they awoke the next morning, the window had been smashed and the special valises holding these sensors and nuclear materials had vanished.