Criminals engage in the same economic reasoning as anyone else. They look at costs and benefits to their actions. This is why we observe certain behavior among them. One might say that the only differences between law-abiding people and criminals are that criminals attribute a low cost to engaging in immoral behavior and that they believe their likelihood of being caught or harmed is low. The cost of engaging in immoral behavior includes a feeling of guilt or remorse, future punishment by a higher being, the potential for going to jail, etc. When the cost of immoral behavior is perceived to be low, and the payoff of immoral behavior is high, people have little regard for behaving morally.
This is why we see news stories such as this one from yesterday, Looting Takes Place in View of La. Police. If we read into the story a bit more, it becomes clear why looting is so rampant. 1) People believe the moral cost of looting is low. People who may have behaved morally prior to the hurricane are now rationalizing their theivery by saying it is "all about survival" or as one looter said when asked whether the items he carried came from his own store, "no, that's EVERYBODY'S store." 2) Other costs associated with stealing from homes and stores are no longer present. There is no store security, no guards to stop them, no cameras to catch their actions and confirm their identity, and even though law enforcement officers are present, they aren't stopping them. As the report says, "With much of the city flooded by Hurricane Katrina, looters floated garbage cans filled with clothing and jewelry down the street in a dash to grab what they could. In some cases, looting on Tuesday took place in full view of police and National Guard troops ... Looters filled industrial-sized garbage cans with clothing and jewelry and floated them down the street on bits of plywood and insulation as National Guard lumbered by." 3) There are benefits to looting, and those benefits are higher in cases where people are hungry or sick.
In this situation, price is not used as a means of rationing because the monetary cost from stealing is zero. However, people still value the items at a value greater than zero and will "pay" for the goods in other ways: by swimming through floods, by using violence, by enduring some level of guilt, sacrificing moral beliefs, etc.
Non-criminals and criminals think alike. The difference is in how they perceive costs and benefits to criminal behavior.