TUCSON — A federal judge found four humanitarian aid volunteers guilty on some of the charges against them for dropping off water and food for migrants at a protected wilderness area along the Arizona-Mexico border, notorious for the number of human remains recovered each year.

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

Hoffman had been charged with operating a vehicle inside the Cabeza Prieta National Wildlife Refuge in southwestern Arizona, entering without a permit, and leaving behind 1-gallon water jugs and cans of beans. The charges stemmed from an encounter with a U.S. Fish and Wildlife officer at Cabeza Prieta on Aug. 13, 2017.

The court found her three co-defendants, all passengers in the truck Hoffman was driving inside the refuge, guilty of entering the area without a permit and abandoning personal property.

"The Defendants did not get an access permit, they did not remain on the designated roads, and they left water, food, and crates in the Refuge. All of this, in addition to violating the law, erodes the national decision to maintain the Refuge in its pristine nature," Velasco wrote in his three-page order posted online Friday afternoon.

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In his decision, Velasco chastised No More Deaths for failing to warn the four volunteers about the full consequences of violating the refuge's regulations. He said all four had acted "in the mistaken belief" that a worst-case scenario for them would have been to get a citation or barred from the refuge.

"No one in charge of No More Deaths ever informed them that their conduct could be prosecuted as a criminal offense nor did any of the Defendants make any independent inquiry into the legality or consequences of their activities," he wrote in his decision.

"The Court can only speculate as to what the Defendants’ decisions would have been had they known the actual risk of their undertaking," he added.

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In a statement, Catherine Gaffney, a longtime volunteer with No More Deaths, criticized Friday’s ruling.

“This verdict challenges not only No More Deaths volunteers, but people of conscience throughout the country,” she said. “If giving water to someone dying of thirst is illegal, what humanity is left in the law of this country?”

The U.S. Attorney’s Office in Arizona, which prosecuted the case, has not responded to requests for comment.

Having been found guilty, each of the four women face up to six months in federal prison and a $500 fine. No date for sentencing has been set yet.

'I was there to leave water'

The trial at the U.S. District Court in Tucson began Tuesday and concluded after three days.

Prosecutors with the U.S. Attorney’s Office in Arizona presented a factual approach, arguing the four women on trial admitted in court to having willingly violated the refuge’s regulations for which they were charged.

The four volunteers testified in their defense that their activities that day were part of sincerely held beliefs to help people in need.

Orozco McCormick said she considered the work almost “sacred,” and described being on the refuge as “like being a graveyard,” because of the number of migrant deaths that had taken place there.

All four also explained that one reason none of them had obtained permits to enter Cabeza Prieta centered around language added to an agreement anyone seeking a permit is required to sign beforehand.

U.S. Fish and Wildlife added the paragraph in July 2017, a month before the incident for which they were cited. It specified that leaving behind food, water, medical supplies and other aid in the refuge was not permitted.

“I was there to leave water,” Hoffman said, when asked why she didn’t sign the document.

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Defense attorneys also claimed that the federal government had singled out No More Deaths, arguing that the volunteers for the organization faced many hurdles that other members of the public didn’t.

That included special instructions for all wildlife officers to refer any member of the organization seeking a permit to the refuge manager, and a “do not issue” list which contained the names of certain volunteers who were not allowed to get a permit.

Lawyers for the four women also cited a July 2017 meeting among members of No More Deaths, wildlife officials and an assistant U.S. attorney, at which the attorney had allegedly said that they were not interested in prosecuting volunteers for dropping off water and food.

Prosecutors dismissed those arguments countering that no written or oral agreement between the U.S. Attorney’s Office to not prosecute these cases existed.

Border Patrol actions part of trial

No one from the U.S. Border Patrol testified in court, but the agency's activities along Cabeza Prieta played a significant role in the trial.

Testimony from both sides highlighted the rising tensions between humanitarian aid groups like No More Deaths and the Border Patrol.

Although several areas of Cabeza Prieta are restricted to the public and aid volunteers, defense attorneys pointed out that Border Patrol agents regularly drive through the areas of the refuge.

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Prosecutors argued that the 10 rescue beacons that the Border Patrol installed inside the refuge was the “preferred way to save lives,” rather than dropping off water jugs with gave “false hope” to migrants, Assistant U.S. Attorney Nathaniel Walters said.

Defense attorneys responded that access to the beacons was key, and that migrants who were dehydrated might not be able to get to them.

What was not discussed during the trial were the accusations from No More Deaths that Border Patrol agents “systematically” destroy or empty water bottles they leave behind for migrants in the desert.

Setting a new precedent?

The guilty verdict is the first of its kind under the administration of President Donald Trump, who has advocated for stricter immigration and border enforcement.

Five other volunteers with No More Deaths face unrelated charges for similar activities on Cabeza Prieta. Their trials are scheduled to begin in the next two months in Tucson.

One of those volunteers is Scott Warren, who also faces a separate trial in connection to his felony arrest in February 2018 on charges of harboring undocumented immigrants.

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Friday’s verdict is the first conviction against humanitarian aid volunteers along the U.S.-Mexico border since 2009, when a federal judge found another No More Deaths volunteer guilty of littering for dropping off water jugs at the Buenos Aires National Wildlife Refuge, west of Nogales.

A year before, Dan Millis was found guilty of littering on the Buenos Aires refuge. However, the 9th U.S. Circuit Court of Appeals overturned his conviction.

Other charges brought against humanitarian aid groups and volunteers mostly had been dismissed.

Follow Rafael Carranza on Twitter: @RafaelCarranza