The STRATFOR report (subscription required) suggests that because the truck the couple was driving had Tamaulipas, Mexico plates (the Hartleys had lived in Reynosa, Mexico before moving to McAllen, Texas five months ago), and then had set out on their jet skis toward a "known battleground" in the war between Los Zetas and Gulf cartels, "it is possible that Zetas scouts identified them as a Gulf Cartel surveillance team."
STRATFOR sources say Los Zetas scouts, known as halcones, had identified the Hartleys' truck as it made its way to Falcon Lake and watched the two set out on their Jet Skis toward the Old Guerrero region. Both Gulf Cartel and Los Zetas operatives have been known to conduct surveillance and countersurveillance operations on personal watercraft, so these scouts thus identified the Hartleys as possible Gulf surveillance assets, given their vehicle's license plate and their method and direction of travel on Falcon Lake. Their description and position was radioed to Los Zetas members on the Mexican side of the lake, after which the couple was apparently confronted by Zetas enforcers.
Tiffany Hartley has said the couple attempted to get away when they saw the boats approaching, and STRATFOR suggests that this action "prompted the men to open fire."
The STRATFOR report also suggests that Los Zetas are in the midst of a "damage control campaign" to "to identify and eliminate those who engaged the Hartleys without proper authorization." The report also cites sources saying that after Hartley was identified as an American, his body was destroyed the same day, to avoid backlash from the U.S. government. Nevertheless, the case has received a large amount of attention, partly because of Tiffany Hartley's omnipresence on national television in the days since. The report suggests that "the decapitation of Flores Villegas was a stern signal to both the United States and Mexico that no body will be produced and to leave the situation alone."
From very early on in the Hartley case, Zapata County Sheriff Sigifredo Gonzalez, the U.S. law enforcement authority most visibly involved in the case, has said that he suspected "lake pirates" tied to the Zeta cartel committed the crime. Back in the spring, after a number of robberies and attempted robberies of people on Falcon Lake by people suspected to be tied to drug organizations, the Texas Department of Public Safety (DPS) issued a warning urging caution on the lake. It issued a new warning after the Hartley incident.
Last week, DPS released a video of the Hartleys being pulled over by a trooper who noticed the trailer carrying their jet skis had expired tags. A clip of the video played on KRGV showed that the truck's plates were obscured by the jet ski trailer.
TPM's call to Sheriff Gonzalez's office to confirm that the plates on Hartley's truck were Mexican was not immediately returned.