A former U.S. Marine who served in Iraq and Afghanistan has been chained to a bed in a Mexican prison since August. Jon Hammar faces up to 12 years in a Mexican jail on what may be a trumped-up charge of possessing an illegal shotgun. Customs officials had already cleared the shotgun before he entered Mexico.

On August 23, Hammar and his friend Ian McDonough were en route to Costa Rica on a surfing vacation when they ran into trouble after crossing the Mexican border.

According to McClatchy newspapers, Hammer brought “a six-decade-old shotgun into Mexico,” which his mother referred to as a “glorified BB gun,” that was passed down to him by his grandfather.

McDonough said the Customs and Border Protection Agent said, “All you have to do is register” the gun, and gave them a registration paper to give to the Mexican authorities.

When Hammar gave the registration form to the Mexican agents, he and McDonough were immediately taken into custody and Mexican prosecutors looked at the “disassembled relic in the 1972 Winnebago motor home” and “dismissed the U.S. registration papers Hammar had filled out,” charging Hammar with the serious crime of “possession of a weapon restricted for use to Mexico’s armed forces”:

Curiously, it wasn’t the type of shotgun that broke Mexican law. It was the length of the barrel, which the formal citation said was shorter than 25 inches, although a discrepancy has emerged over how the barrel was measured.

It is worth noting Mexico’s gangs “routinely wield AK-47 and AR-15 assault rifles, high-powered .50-caliber sniper rifles, rocket-propelled grenades and other potent weaponry,” and Hammar’s shotgun is rendered useless against such high-powered weapons.

The Mexican lawyer representing Hammar said he faces three to 12 years in a Mexican federal prison if convicted on the gun charge. Mexican authorities released McDonough, Hammar’s friends, who was able to walk back to Texas, most likely because he had been living part-time in Argentina.

Marine Sgt. James Garcia served with Hammar in various combat situations and said he was heartbroken because Hammar was “one of the best we had.” According to McClatchy, Hammer, now 27 years of age, “joined the Marines and deployed to Afghanistan and Iraq before receiving an honorable discharge in 2007, serving another four years in inactive reserve.”

After Hammar was sent to a state prison in Matamoros, his parents in Florida received phone calls demanding $1,800.

According to McClatchy, Hammar’s family did not pay the extortion and contacted U.S. diplomats, who got Hammar into solitary confinement and out of the wing controlled by a Mexican drug cartel.

This is not the first time Mexican authorities have captured an American on dubious gun-related charges. Mexican officials arrested a Dallas truck driver in April, “carrying 25,000 pounds of ammunition in his 18-wheeler,” after Customs and Border Protection agents instructed him to briefly cross the border to make a U-turn. Mexican prosecutors “charged him with crimes that could have brought more than 25 years in prison” but — after Congressional intervention — they ultimately released the truck driver (Jabin Bogan) on November 23.

Rep. Ileana Ros-Lehtinen (R-FL), who is the chairwoman of the House Foreign Affairs Committee and the Hammars’ Congresswoman, said she would do her best to help the Hammar family get their son back from Mexican authorities.

“His family has described a very disturbing situation that includes their son being chained to a bed in a very small cell and receiving calls from fellow inmates threatening his life if they did not send them money,” Ros-Lehtinen said. “The family also says that the jail where their son is being held is controlled by the dreaded and brutal Zetas drug cartel. The family wants their son back home, and I will do my best to help them.”

Garcia, who served with Hammar, emphasized how the United States should not leave one of its own behind.

“He doesn’t deserve this,” Garcia told McClatchy. “We never leave a brother behind. We never leave a Marine behind. We have to do something.”