Four men have been charged as suspected members of an auto theft ring renting high-dollar SUVs from rental agencies at Denver International Airport and never returning them, the Rocky Mountain News reports.

The SUVs were rented two at a time, apparently to be taken across the border into Mexico, said Lynn Kimbrough of the Denver District Attorney's Office.

Hertz, one of the victims, reported SUVs also were stolen in Phoenix and Tucson and estimated its losses at nearing $1 million, Kimbrough said.

The group, using fictitious driver's licenses from Mexico and Arizona, is believed to have stolen six vehicles from DIA car rental companies in August, according to arrest documents.

Two of the six stolen SUVs were recovered at the U.S.-Mexico border by border agents, but the drivers fled, documents said.

Another vehicle was recovered in Phoenix. The other three are still missing and believed to be out of the country, police said.

On Sept. 9, four more SUVS were stolen from rental agencies at DIA. One was found abandoned in Fruita in western Colorado and the other was recovered in Utah after it was totaled when it hit a cow, according to police.

According to the Rocky Mountain News, the four suspects were arrested Sept. 29 after one car rental agency reported that two men with Mexican driver's licenses had tried to rent SUVs. Another agency reported that they were believed to be the same two men had tried to rent SUVs earlier.

Detectives subsequently arrested two additional suspects and recovered the vehicles, police said.

The suspects were identified as Marco Nunez-Peralta, 33, Zerafin Munoz-Lozano, 31, Ramiro Escarsega, 19, and Ismael Marrufo, 19.

Marrufo was charged with 10 counts, including theft, conspiracy to commit theft, attempted theft, forgery, criminal impersonation and possession of forged instruments. The others face fewer charges.