MIAMI (CBSMiami) – A Palmetto Bay man who survived wars in Iraq and Afghanistan is now locked in a legal battle South of the border.

Jon Hammar, a 27-year old former Marine, was arrested this summer in Mexico because he carried an antique shotgun over the border. His parents said it was an honest mistake and are now enlisting help to free him.

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Thursday morning they, along with their supporters, gathered at U.S. Representative Ileana Ros-Lehtinen’s office in South Florida.

John’s mother, Olivia, said he’s not doing well.

“In addition to being somewhat hopeless he is in enraged, and hyper vigilant and in combat mode, which is what he was trying to recover from,” said Hammar.

The Hammars went public with their story a week ago, four months after Jon was locked up, because all diplomatic efforts seemed to be getting nowhere.

Hammar’s troubles began in August when he took off with a buddy to Costa Rica to surf and deal with post traumatic stress from the war.

Once across the border, though, he was immediately arrested, placed in a notoriously dangerous prison some say is run by a drug cartel and charged with bringing a firearm into the country – a federal crime.

“We started receiving calls from members of the cartel saying, we have your son and we’re going to kill him. And then they’d put him on the phone, and I realize that they really did,” said Olivia Hammar.

The rifle, a family heirloom, was actually cleared by U.S. Customs.

“Customs weighed the gun, measured the gun, I think took pictures of the gun and gave him paperwork to fill out and then he took that paperwork across to the Mexican side, declared the gun and was immediately arrested,” said Olivia Hammar.

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In a statement, a spokesman for the Mexican Embassy stressed that possession of any weapon restricted for the use of the army in Mexico is a federal crime and must automatically be prosecuted.

“All it is, is that the barrel of the rifle was this length or the other length. It was not like he was trying to start a militia,” said Ros-Lehtinen.

Olivia said her son spends his days shacked to his bed, reading a bible.

“He’s hanging in, he’s tough. A lesser person would have pleaded guilty. Because they have brought him in without counsel to courts and harassed and told him you need to just plead guilty and he’s said ‘I’m not doing it’. God bless the Marine Corp for doing that,” said Olivia Hammar.

His friends have started a petition requesting his release.

“We are not going to rest until he comes home,” said Jessica Fernandez, a friend.

More than 9,000 people have signed the petition but it’s still unclear whether going public with the situation will help.

“He is just a really tough situation. It’s public in Mexico at this point so we are just praying for his protection and is release,” said Olivia.

Ros-Lehtinen said she plans to talk with Secretary of State Hillary Clinton next week and the hope is to bring Hammar home by Christmas.

“It has to happen,” said Olivia Hammar. “This is going to be, this is going to get you home.”

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Hammar is due in court late next month. If convicted, he faces up to 12 years in prison.