(CBS News) LOS ANGELES - Twice in a week, young men have stormed into buildings and started shooting, firstlast Friday, and then on Monday night . Mental illness seems to be at the center of many of these shootings as we learned more about the strange beliefs of the alleged L.A. airport killer.
The FBI agents who searched Paul Ciancia's apartment had a search warrant for his cell phone. They found it in his roommate's car.
The warrant states they were looking for information "relating to Ciancia's views on the legitimacy or activities of the United States Government, including the existence of a plot to impose a New World Order..."
Shortly after the rampage, which took place at the airport's Terminal 3, police say they found a one-page letter in Ciancia's bag. It said he targeted TSA agents to "instill fear in your traitorous minds" and also mentioned "NWO," or new world order. That's a century-old conspiracy theory, according to Mark Potok who tracks extremist groups.
"[It] basically identifies the federal government," he said, "as an evil malefactor that is involved in a conspiracy to force the United States into a so-called one world government known as the new world order."
People who believe this theory are deeply suspicious of international organizations, such as the United Nations, and think the government plans a national seizure of all guns.
"They believe that the federal government intends to impose martial law on the country at any moment now," said Potok, "that that martial law will be imposed with the help of foreign troops probably U.N. blue helmets."
Online talk shows perpetuate these anti-government views and often mention TSA officers. But so far, there is no evidence yet that the alleged LAX shooter was a member of any such group. In fact, besides his letter, he left very little in the way of a paper trail -- no obvious online writings or other so-called manifestos.