In 2009, Najibullah Zazi sent three e-mails from his Aurora apartment to a suspected terrorist in Pakistan asking about the ingredients necessary to bake something for an upcoming marriage.
Within hours, the Federal Bureau of Investigation was on to him.
Agents monitored his calls. They followed him across the country. They became particularly alarmed when they learned he had purchased large quantities of hydrogen peroxide, a hair dye.
Almost three years later and 15 miles away, James Eagan Holmes was filling his home with armament. He had regular deliveries of ammunition for a military-style AR-15 rifle, two handguns and a shotgun he purchased over the course of 60 days. There were about 6,000 rounds in all, another 300 shotgun shells and a high-capacity drum for the rifle. In all, it amounted to more than 200 pounds of ordnance.
All of it legal. None of it, apparently, noticed by or reported to police. None of it the slightest bit disconcerting to ammunition suppliers, delivery drivers or neighbors.