The mother of Sgt. Andrew Tahmooressi, who has been held in a Mexican jail for three months, has appealed to the top U.S. diplomat in Mexico, seeking his help in getting the Marine released.

Jill Tahmooressi sent a letter to U.S. Ambassador E. Anthony Wayne on June 30 urging him to get a Mexican federal judge to expedite the review of the 25-year-old's case, Fox News reported.

"If any consideration can be made to expedite the reviews before the federal judge so that he will be closer to probable freedom, those actions would be much appreciated," Jill Tahmooressi wrote.

She noted that Friday is the Fourth of July and will be a somber one for her family and friends, who will not be able to celebrate the holiday with the sergeant.

"This Independence Day will be a bitter one for Andrew, his family and supporters as his freedom is bound by his felony arrest," Jill Tahmooressi wrote. "Freedom he valiantly fought for others to have, willing to die to combat the evil of oppression and violence, Andrew is experiencing captivity for the first time, in a foreign country as a result of one wrong turn."

On March 31, Tahmooressi was arrested after he said he accidentally crossed the U.S.-Mexico border in his pickup truck while possessing three firearms that are illegal in Mexicio but that he legally purchased in the U.S., according to CNN and other sources.

Tahmooressi is from Florida and had just moved to San Diego, where he was supposed to receive treatment for post-traumatic stress disorder, which he got from serving two tours in Afghanistan. He claims he got lost and confused about the signage along San Diego's roads near the border.

Despite the support from his mother, top U.S. officials and other advocates for a speedy release, attorney Fernando Benitez said Tahmooressi would still have go through the Mexican judicial system at its normal pace.

However, the process seems to have hit a few snags, as both of the Marine sergeant's previous attorneys failed to submit evidence to the court, Fox reported.