SAN DIEGO -- There's no dispute retired Marine Sgt. Andrew Tahmooressi drove with three loaded guns in his truck into Mexico where firearms are illegal.
Tahmooressi says he got lost on a California freeway ramp that sent him across the border with no way to turn back. His attorney argues Mexican Customs officials also violated his rights by holding him for some eight hours without notifying the U.S. Consulate or getting a translator.
But arguing those points could mean a long time in jail for the 26-year-old Afghanistan war veteran.
Instead, his lawyer is relying on another argument to win his freedom in the shortest time possible: He needs to be release so he can go home to get treatment for his combat-related post-traumatic stress, which Mexican authorities don't treat, even in their own soldiers.
The case marks one of the first times Mexico could make a ruling on PTSD -- though the psychological wound is increasingly used in U.S. courts, especially in arguing for reduced sentences.
But it has gotten mixed results, according to a study by the University of California, San Francisco. U.S. appeals courts have found PTSD-based criminal defenses to be viable when a direct connection is made by an expert between the criminal actions and PTSD, the study found.
That U.S. case law could serve as an important reference point for courts in other countries, the authors' noted. Mexico, however, has a long history of staunchly keeping U.S. influences at bay and it is particularly sensitive of any perceived pressure on its courts from its neighbor.
At the same time, Mexico has prided itself on considering humanitarian concerns -- which is why Tahmooressi's lawyer, Fernando Benitez, believes his client's PTSD will help in fast-tracking his return home.
The seasoned lawyer, who has successfully defended well-known names south of the border, said he is not using PTSD as a defense as the Marine's previous lawyer tried to do before Tahmooressi fired him.
That would mean then that Tahmooressi admits a wrongdoing caused by PTSD, and the Florida man maintains his innocence.
Using PTSD as a defense also could backfire with Mexico deciding that he is mentally incapacitated and sending him to a mental institution, legal experts say.
Benitez instead is asking the judge to rule in his favor so he can get PTSD treatment.
Benitez said his client carries loaded guns with him because his weapons, which were bought legally in the U.S., make him feel safer, and he is often distracted, which could have contributed to him becoming lost.
"He suffers from the hunter-prey syndrome," Benitez said. "He feels the need to protect himself at all times."
His mother, Jill Tahmooressi, says his time in a Mexican jail has been worse than his two tours in Afghanistan, where he took heavy gunfire and performed first aid on a bomb technician whose legs were severed in an explosion.
"He's fighting constantly just to stay sane," said his mother, who talks to him daily.
A psychiatrist hired by Mexican prosecutors, Dr. Alberto Pinzon, noted in his Sept. 30 report that Tahmooressi feels like he is constantly in danger and is in a constant state of alertness. He recommended Tahmooressi get PTSD treatment in the U.S.
The prosecution said Tahmooressi visited Mexico at least four times before and the border is well marked about entering Mexico. The government said now it's up to its court system to decide the outcome.
"In Mexico, as in the United States, ignorance of the law, error, or failure to understand the consequences of violating the law do not exempt individuals from responsibility, regardless of intention," the Mexican embassy in Washington said.
Tahmooressi left Florida for San Diego in January to get help after dropping out of college, unable to concentrate or sleep, his mother said. He was getting settled and starting therapy.
Before he was arrested, Tahmooressi said he had gone to Tijuana on foot, and left his truck at a U.S. parking lot.
When he walked back to his truck to drive home March 31, his attorney said, he took a wrong turn and he was funneled into a Mexican port of entry with a rifle, shotgun, pistol and hundreds of rounds of ammunition in his truck.
In Mexico, possession of weapons restricted for Army use is a federal crime, and the country has been tightening up its border checks to stop the flow of U.S. weapons that have been used by drug cartels.
After being jailed in Tijuana, Tahmooressi's mother said, he tried to kill himself by cutting his neck with a shard from a light bulb in his cell because the guards and inmates threatened to rape, torture and kill him and he feared she would be in danger.
He has since been transferred to another prison. A pastor visits him regularly and the Mexican government says he is under medical observation.