PHOENIX – A federal judge in Tucson overturned the convictions of four humanitarian aid volunteers found guilty last year of leaving food and water for migrants trekking through protected Arizona wilderness, saying their work was part of their "sincere religious beliefs."

In January 2018, U.S. Magistrate Judge Bernardo Velasco found Natalie Hoffman, a volunteer with humanitarian aid group No More Deaths, guilty on all three charges she faced. He also found three other volunteers – Oona Holcomb, Madeline Huse and Zaachila Orozco-McCormick – guilty of the two charges each.

Their convictions came from citations they received on Aug. 13, 2017, for entering Cabeza Prieta Wildlife Refuge without a permit, and leaving behind 1-gallon water jugs and cans of beans at drop stations in the refuge that No More Deaths has used for years.

On Monday, U.S. District Judge Rosemary Márquez issued a 22-page decision reversing Velasco's guilty verdicts for all four volunteers, after the four appealed their convictions.

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"Defendants met their burden of establishing that their activities were exercises of their sincere religious beliefs, and the Government failed to demonstrate that application of the regulations against Defendants is the least restrictive means of accomplishing a compelling interest," Márquez concluded.

Monday's reversal of the four convictions is the latest blow to government prosecutors who sought to take a tougher stance and prosecute humanitarian-aid workers in the past two years.

In November, a Tucson jury acquitted No More Deaths volunteer Scott Warren on felony harboring charges for helping two undocumented migrants who showed up to the "Barn," a building in Ajo used by humanitarian-aid volunteers to launch water drop-offs and rescues along Cabeza Prieta and the Organ Pipe Cactus National Monument.

On the same day as the verdict, the judge presiding over the case acquitted Warren of a misdemeanor for leaving behind water at Cabeza Prieta on another occasion, also citing his religious beliefs.

But the judge found Warren guilty of operating a motor vehicle on a restricted road inside the refuge. He set a sentencing hearing for that misdemeanor for Feb. 18.

No More Deaths said Monday's ruling reaffirmed their belief that "humanitarian aid is never a crime." In a written statement Tuesday, they also vowed to continue doing their work in the Arizona desert.

"The reversal of convictions is a victory for all people of conscience and righteousness who seek to end the death and suffering in the borderlands," volunteer Alicia Dinsmore said. "People continue to die every day on Cabeza Prieta and we will continue to act on our moral imperative to do this vital work."

The U.S. Attorney's Office in Arizona, which prosecuted the case, said they were very disappointed and disagreed with Márquez's opinion.

Assistant U.S. Attorney Heather Sechrist told The Arizona Republic that the office is weighing all options, but that they haven't decided whether they will seek an appeal. They have 30 days to decide.

"Our border enforcement agency partners work hard every single day, and they're gonna keep working to protect the borders and aggressively enforce federal law, and we do intend to do so as well," Sechrist said.

Follow Rafael Carranza on Twitter: @RafaelCarranza.