VEKOL VALLEY, Ariz. â€"  Five bodies burned beyond recognition have been found inside the shell of a charred sport utility vehicle in the Arizona desert, and Pinal County Sheriff Paul Babeu said Saturday the case is likely connected to drug cartel violence.

Only 70 miles from the U.S.-Mexico border, Pinal County is concerned about the extent of the violence, Babeu said.

"This is pretty significant," he said of the latest homicide investigation. "Given all these indicators, you don't have to be a homicide detective to add up all this information."

Pinal County deputies were involved in more than 350 high-speed pursuits last year, and Babeu said most of those involved cartel members. There have been shootings, the bodies of murder victims have been left in the desert and just this week, several loads of drugs were confiscated, he said.

"This happens far too often and usually our involvement is just a small percentage of what really goes on," the sheriff said. "Is it concerning? Is it troubling? Yes it is."

The latest case started around 4:30 a.m. in the Vekol Valley area when a white Ford Expedition was spotted by a Border Patrol agent. The vehicle disappeared despite an effort by federal and local authorities to track it down. Why the vehicle drew attention is unclear.

At daybreak, an agent spotted tracks leading from Interstate 8 into the desert. The vehicle that left the tracks had apparently launched off the highway, going airborne for a short distance before landing in the desert. The tracks continued on for a couple of miles.

Agents could see the smoldering vehicle from a distance through binoculars.

They approached with extinguishers. Inside, they found the bodies -- one in the rear passenger seat and four lying in the back cargo compartment. The front seats were empty, Babeu said.

The bodies were so badly burned that investigators could not immediately determine their gender or ethnicity. While it's unclear whether the victims were from Mexico, the sheriff's office has notified the Mexican Consulate.

Babeu said investigators will try to determine whether the victims were dead before the SUV was set ablaze or whether they were alive when the fire was started.

"Clearly these people were murdered, but we don't know the manner of death," he said.

The sheriff said the extent of the violence, particularly in the western part of the county -- about 35 miles south of Phoenix -- is a concern. He said it's more evidence that drug smuggling north of the border continues to be significant and has not subsided.