Volunteers with a local humanitarian aid group stopped Border Patrol agents from entering their camp outside of Arivaca to search for people whose footprints they said they followed there.

“Our standard practice and policy has always been to dialogue with Border Patrol,” said Geoffrey Boyce, a spokesman with No More Deaths. But unless agents have a warrant to search the camp, he said, they have no reason to be there.

The problem, said Art del Cueto, president of the Border Patrol Union Local 2544, is that agents don’t know if the people they are tracking are dangerous or are human or drug smugglers.

“Bottom line, you don’t know who these people are,” he said, and No. 2, they broke the law and an agent’s job is to protect the border and arrest people who enter the country illegally.

On Thursday afternoon, two Border Patrol agents went inside the camp, located on private property about 20 miles from the border, without permission and without speaking with any of the volunteers, Boyce said Friday.

A volunteer told the agents they couldn’t be there and they left after being asked to do so. But later that evening, another agent returned and asked for permission to search the camp. Volunteers declined. Four Border Patrol vehicles then stayed just outside the camp through Friday morning, when all but one left, Boyce said.

Agents don’t go into private houses or the curtilage, Tucson Sector Chief Manuel Padilla said, unless it’s an emergency situation or get a warrant, which agents weren’t able to secure Thursday. “In this case we can wait it out,” he said, and agents will be watching the area closely.

When the agents first arrived at the camp, three people were receiving overnight medical care, Boyce said. That included a 50-year-old man who was lost and arrived vomiting, along with a 17-year-old girl and a 35-year-old woman. The pair had been lost in the desert for about two weeks. The 35 year old also had third-degree burns from a cooking fire.

The camp, which opened in 2004 and sits on property owned by popular children’s author Byrd Baylor, is near the Papalote wash, which Boyce said is a high-trafficked area and they don’t know if the agents were tracking a different group. The Border Patrol said they followed footprints that led them to the camp and couldn’t find any others leaving.

No More Deaths volunteers go on daily excursions on foot looking for people in distress, while medical staff is available on site to provide care, organizers said. People normally get treated and leave on their own or they contact Border Patrol when they want to turn themselves in.

The group’s mission is to prevent deaths on the border, said Margo Cowan, their legal advisor. More than 2,000 remains have been found in Southern Arizona since 2001.

But when does it end being medical assistance or rendering first aid and starts going into aiding and abetting or harboring, asked Padilla.

“Getting them first aid that’s fine,” he said. But when the person no longer needs medical assistance, that’s when it becomes a harboring issue, he said.

To del Cueto, the group could be harboring border crossers by not letting agents search.

Case law is not 100 percent clear on what harboring is, said Lynn Marcus, co-director of the immigration law clinic at the James E. Rogers College of Law at the University of Arizona.

“If you are openly allowing somebody into your property to render medical assistance for dehydration,” for example, she said, and only for the time the person needs to recover, there’s an argument that they are not illegally harboring.

The law is always interpreted on a case-by-case basis, she said, and this argument has never been tested.

In 2005, two No More Deaths volunteers were arrested near Arivaca with three border crossers they were driving to Tucson to get medical care. They were indicted by a grand jury on charges of conspiracy to transport and transportation of an illegal alien.

A federal judge dropped the charges in 2006 because he said they were following guidelines that border volunteers had been using for several years without being arrested.

The incident spurred the campaign “Humanitarian Aid is Never a Crime,” printed on yard signs and bumper stickers.

Then in 2009, volunteers were cited by the Fish and Wildlife Service for littering for leaving water jugs out for immigrants. A federal appeals court ruled in 2010 that human-rights activists can’t be charged with littering for leaving bottles of water for immigrants on federal property.

The organization has been negotiating with Border Patrol’s leadership in Tucson for years to acknowledge their right to provide humanitarian assistance, Cowan said.

“We believe that the work we do in the desert is legal,” said Cowan, a migrant-rights activist and local attorney. “We are not sneaking around doing something that’s illegal.”

The Border Patrol has a working relationship with No More Deaths and other humanitarian aid organizations, Padilla said, but there are still challenges.

“We continue to engage with the community and nongovernmental organizations to achieve the mission of saving lives or rendering medical aid to people who need it,” he said, “but we also need to achieve our mission.”

Contact reporter Perla Trevizo at ptrevizo@azstarnet.com or 573-4210. On Twitter: @Perla Trevizo