In the desert within 35 miles of one of the nation's largest cities and about 70 miles north of the U.S.-Mexico border, Arizona authorities found a car ablaze with five bodies burned beyond recognition inside.

The location of the smoldering car in a known smuggling corridor and the nature of the crime itself have Pinal County Sheriff Paul Babeu saying that he's all but certain a violent cartel is responsible.

The area known as the Vekol Valley where the bodies were found has been the scene of shootouts among smuggling groups fighting over loads of drugs or illegal immigrants, high-speed pursuits and major drug seizures. The area is so heavily trafficked that at one point the Bureau of Land Management posted signs warning the public that "may encounter armed criminals and smuggling vehicles traveling at high rates of speed."

The Pima County Medical Examiner's Office was conducting autopsies on the five bodies Monday, two days after they were found in a vehicle so badly torched that the license plate was unrecognizable. The coroner will have to rely on dental records in an effort to identify them.

The autopsies also will determine whether the five people were killed before they were burned or whether they were alive when the car was set afire.

It's unclear how soon results of the autopsies will be released.

For now, Babeu and his deputies are treating it as a smuggling-related crime, possibly one cartel targeting rivals and burning the car in an effort to hide evidence and evade authorities.

If that is confirmed, the incident would be the latest in spillover violence from Mexico, which mostly affects those involved in the smuggling world or their human cargo.

"It's very alarming to me as the sheriff here that there could be this level of deliberate violence," Babeu told The Associated Press on Monday. "This normally does not happen in the United States, and this happened 70 miles north of the border and 30 miles south of America's sixth-largest city. If this is in fact connected to the cartels, and we absolutely prove it, this should be a warning to our country."

Babeu said that the burned car likely is the same car that a Border Patrol agent saw four hours earlier Saturday when it was still dark outside.

The agent saw a white Ford Expedition stopped and became suspicious, but when he approached, the car fled and the agent lost it, Babeu said.

When the sun came up, the same agent saw car tracks in the area leading into the desert and shortly after found a smoldering white Ford Expedition, Babeu said.

When the agent approached the car, he saw four burned bodies lying down in the cab of the vehicle, and one body in the back passenger seat; no one was in the driver's or front passenger's seat.

The bodies were burned so badly that Babeu said investigators don't yet know their gender, race or ages.

Babeu declined to say whether other vehicle tracks or footprints were found around the vehicle, saying that he did not want to compromise the ongoing investigation and manhunt.

Spokespeople for the Border Patrol and U.S. Immigration and Customs Enforcement confirmed that their agencies were supporting the sheriff's investigation but declined to answer further questions.

If investigators confirm that a cartel is responsible for the killings, it would be one of the most extreme examples of spillover violence in the U.S., said Eric Olson, associate director of the Woodrow Wilson International Center for Scholars' Mexico Institute in Washington, D.C.

"This sort of violence is highly unusual," Olson said. "It's a horrible, horrible thing, but we don't see that happening in a lot of places."

He said there's no reason to believe that the incident is the beginning of a new pattern of behavior by cartels or that the violence will start affecting more Americans.

"I think it would be more concerning if it were downtown Phoenix," Olson said. "But the surest way to attract enormous amounts of law enforcement interest is to kill five people and burn their bodies in downtown Phoenix. They're not that stupid."

George McCubbin, president of the National Border Patrol Council, the agency's union, said he has no doubt that the burned bodies were the work of a cartel.

Although a law enforcement task force has been assigned to the area, McCubbin said there's not nearly enough manpower to address the volume and seriousness of the crimes. "It's fair game for the smuggling operations," he said.

Michael Vigil, a former DEA chief of international operations who worked part of his career on the California and Arizona borders with Mexico, said the killings are an extreme example of a pattern of increased kidnappings, shootings and other violence on the U.S. side of the border.

"When you have a massive drug trade that spans both sides of the border, you're going to have violence," he said.

Among high-profile examples of spillover violence suspected or confirmed to be tied to smuggling cartels was the October 2010 killing of Alejandro Cota-Monroy, a former smuggler who was bludgeoned, stabbed and then decapitated in a suburban Phoenix apartment, likely because he stole from the cartel he worked for — a gruesome killing that police say was meant to send a message that anyone who betrays the traffickers will get the same treatment.

In March 2010, Arizona rancher Robert Krentz was gunned down while checking water lines on his property near the border. Authorities believe — but have never produced substantive proof — that a scout for drug smugglers was to blame for his killing.

And in May 2009, a Mexican drug cartel lieutenant who became an informant for U.S. Immigration and Customs Enforcement was shot eight times outside his pricey home in El Paso. The lieutenant, Jose Daniel Gonzalez Galeana, was living in Texas on a visa that ICE gave him, and is believed to be the first ranking cartel member killed in the U.S.


Associated Press writer Elliot Spagat contributed to this report from San Diego.


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