Doing some lunchtime reading, I find the prosecutor's behavior incredibly hard to understand.

Prosecutors repeatedly rebuffed Voth's requests. After examining one suspect's garbage, agents learned he was on food stamps yet had plunked down more than $300,000 for 476 firearms in six months. Voth asked if the ATF could arrest him for fraudulently accepting public assistance when he was spending such huge sums. Prosecutor Hurley said no. In another instance, a young jobless suspect paid more than $10,000 for a 50-caliber tripod-mounted sniper rifle. According to Voth, Hurley told the agents they lacked proof that he hadn't bought the gun for himself.