Three-time Edgar-winner T. Jefferson Parker researches his novels meticulously to ensure their authenticity, but the information he uncovered about the accessibility of guns and ammunition in the U.S. while writing Iron River, out this month from Dutton, brought about some disturbing revelations. The third Parker novel to feature Deputy Charlie Hood, Iron River takes place amid the violent flow of weapons between the U.S. and Mexico along the border that runs from San Diego to Corpus Christi, Tex. In the last three years, 15,000 Mexicans have been murdered by drug cartels south of the border, and nearly all of the guns used came from American manufacturers. One of the characters in Iron River has to buy a large quantity of ammunition, which sent Parker to a shooting sports Web site called cheaperthandirt.com to find out how such an order could be placed by an individual.

“There's a live chat customer service function on the Web site, and I told my rep Wes that I wanted to purchase 50,000 rounds of .32-caliber automatic Colt pistol ammunition.” When Wes returned online, he informed Parker they were out of stock on the item, but would have it the next day and would be happy to drop-ship the order to Parker via two-day delivery. “I asked the guy, 'If you did have it in stock, how much would it cost?' and he quoted me a price of $19,750. It was that simple. The guy was very matter-of-fact.” Currently, all that's required to buy ammunition or guns in the U.S. is a clean criminal record and a minimum age of 18. “We've got to get a handle on these guns,” Parker said.

In the context of the mystery novels he's famed for, Parker has researched subjects from the gruesome to the near slapstick. He attended a college mortuary sciences class while writing Blue Hour (1999) to find out how a portable embalming machine works. “It runs on gravity and it's called a Porti-Boy. Of course, my bad guy in the book used it to preserve his 'dates,' ” Parker said. His visit to an inmate at Pelican Bay State Prison in California, which houses “the worst of the worst” criminals, helped him write Storm Runners (2007). “I was visiting a pen pal who was in solitary there. He was an older, little white guy in for a triple murder, life without parole,” Parker said. The inmate told Parker he wanted to remain in solitary. “When I walked out of the visitation room a couple of hours later, I saw why. The other inmates were Mexican mafia, big, young, tattooed, and packing murder in their eyes. They ran the place.”

As daunting as these experiences were, nothing could have prepared Parker for the truth about how easy it is to acquire guns and ammunition in this country. A gun owner himself who comes from a family of hunters and is skilled and comfortable with firearms, Parker was appalled by the unregulated status of ammunition. “The murders in Mexico are directly related to drugs, and the U.S. is supplying the guns that are used. This problem is manifest—it's about U.S. drug cartels as well.”

Parker is pleased with legislation that California's governor, Arnold Schwarzenegger, recently signed that requires maintenance of purchaser records by handgun ammunition dealers. It also stipulates that such sales must be completed face to face, rather than over the Internet, as in Parker's faux attempt.