Updated

The plight of Marine veteran Jon Hammar, who has been in a Mexican prison for four months on what is being called a trumped-up federal weapon charge, has gained social media momentum, with a growing campaign calling for his release.

Anchoring the effort is www.facebook.com/FreeJonHammar, which has not only maintained news updates on his case but has also served as a venue for concerned citizens to express their frustration and anger at how the 27-year-old veteran of multiple tours in Iraq and Afghanistan is being treated in the notorious CEDES prison in Matamoros, Mexico.

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"We never leave a brother behind. We never leave a Marine behind. We have to do something," screams the title of the page.

Hammar was arrested Aug. 13 in Matamoros after he declared to Mexican customs agents a shotgun he planned to use for hunting in Costa Rica with fellow Marine veteran Ian McDonough. McDonough was also arrested, but later released because he did not own the weapon.

Prosecutors contend the rifle, an antique .410 gauge shotgun, is used by the Mexican military, a fact which has been refuted by high-ranking military officials, according to Hammar's attorney Eddie Varon-Levy. The Sears Roebuck model shotgun also falls within the parameters of Mexican regulations for bringing a hunting rifle into the country. Hammar's only perceived failure was to have the appropriate documentation.

Hammar's arrest and confirmed incidents of death threats, extortion, and being chained to his bed in a prison controlled by members of the Los Zetas and Gulf Cartels have fueled national anger, which has been vented on the Facebook page.

With nearly 4,000 likes, the sentiments are vividly clear.

"Look i am a combat vet i am so tired of our government doing nothing......i have my own weapon and ammo and i know of other vets who would willing go and do what our government want do and that is to go down and get him.....NO ONE LEFT BEHIND," said Mike Walters in a post.

While many contributors advocated direct military SEAL-like rescue missions, others expressed frustration in failed diplomatic efforts.

"This is an absolute outrage, where is our government? This man served this country and is an American citizen," said a poster identified as Anthony Greene.

U.S. Consulate officials in Mexico told Hammar's family there is little that can be done diplomatically because of Mexican sovereignty.

Some of the Facebook comments provided political and economic suggestions.

"Boycott travel to Mexico. When the Mexican government admits that they are powerless over the drug cartels -- why would we support them?" said Debbie Blair.

Seeing a lack in tangible diplomatic support, Hammar's supporters are petitioning the White House for action.

Jon Hammar Sr., said his daughter, Jon Jr.'s younger sister and classmates at Wingate University in North Carolina, launched the petition campaign to bring her brother home. Hammar Sr., said, for his daughter's safety, he requests keeping her from the press.

There are currently two active petitions. One at www.Change.org and the other directly petitioning President Barack Obama and the White House for action, https://petitions.whitehouse.gov/petition/help-bring-jon-hammar-home

As of Saturday there were more than 15,500 signatures on the presidential petition, which requires 25,000 for review. Cited in the reasons for the petition are civil rights and liberties, human rights, and the rights of veterans and families.

Hammar supporters can also go to the Twitter hashtags #freejonhammer and #bringjonhammarhome.

Joseph J. Kolb is a regular contributor to FoxNews.com