"We know where it started and when it started, but (the specific cause) is under investigation," Tidwell said hours later from southern Arizona. "When we do have that information, we will share it."  But in a press conference, Arizona Sen. John McCain blamed illegal immigrants for starting unspecified fires in that area.  "There is substantial evidence that some of these fires have been caused by people who have crossed our border illegally," McCain said. "The answer to that part of the problem is to get a secure border.  The Republican senator said that illegal immigrants set such fires either to send signals, keep warm or distract law enforcement agents. But he did not specify which fires allegedly had been started by illegal immigrants, nor identify his sources or provide details of the "substantial" evidence he cited.  Randy Parraz, a civil rights advocate who ran unsuccessfully against McCain as a Democratic candidate in 2010, called McCain's remarks suggesting illegal immigrants caused the fires "careless and reckless" but not entirely surprising given the political climate in Arizona.  "You have to have some sort of factual basis: John McCain should know better," said Parraz, a co-founder of Citizens for a Better Arizona, which is working to recall state Sen. Russel Pearce, the primary sponsor of Arizona's controversial anti-illegal immigration law. "It's easier to fan the flames of intolerance, especially in Arizona."  Parraz said it is particularly distressing that immigrants are being blamed for destructive fires, at a time when many are also being targeted given the state's unemployment, foreclosure and other economic issues.
As discussions swirled about its origins and impact, the U.S. forest service chief deemed a raging wildfire in southern Arizona as "the number one priority" for firefighters nationwide."The