By Eduardo Rojas / e.rojas@latinospost.com (staff@latinospost.com) | First Posted: May 02, 2012 12:28 PM EDT

Maria Guadalupe Güereca Betancourt is the mother of teen Sergio Adrián Hernández shot to death by a border patrol officer back in June 2010.

Maria Guadalupe told the Huffpost that she no longer believed in U.S. justice after the U.S. Department of Justice announced that no criminal charges would be filed against the officer, Jesús Mesa Jr., who fatally shot her 15 year-old son back then.

"I feel frustrated, disappointed, because they will not file criminal charges against the officer who fired at a boy despite all evidence of testimonies and videos. How can I believe in U.S. justice?" she continued telling the Huffpost.

The incident took place in a bridge linking El Paso, Texas and Ciudad Juarez, México when officer Mesa reportedly fired at the teen after he and his colleagues were being

targeted with stones.

Mesa claimed he was acting on self defense and on Friday, after a multi-party investigation, the Department of Justice ruled that Mesa had "not acted inconsistently with border patrol protocol nor with his training in using lethal force."

According to investigations the officers were responding to an operation intended to smuggle immigrants into the U.S. through the bridge.

After the ruling was announced, the Mexican government responded with an announcement of its own saying that it "would use all diplomatic and international legal resources in its reach" to bring justice to the family's victim.

The incident caused friction between both nations last year with angered Mexicans demanding justice in cases involving killed other migrant Mexicans.

The U.S. on the other hand has not relaxed its firm stance on immigration issues as a result.