What they left behind: Items found in the Borderlands

Human rights activist John Fife, who has advocated for the sanctuary movement since the 1980s and was a co-founder of No More Deaths in 2004, addresses volunteers gathered with the Tucson Samaritans for their annual event Flood the Desert, on July 1 in Tucson, Arizona.

A toothbrush left by a migrant near Three Points, Arizona.

Volunteers with the Tucson Samaritans gather water and medical supplies to take into the desert in southern Arizona.

Sun-bleached camouflage pants left by a migrant near Three Points, Arizona. Volunteers say migrant people abandon the faded clothing they walked in for their best outfits carried in a backpack when they attempt to blend into life in the U.S.

Humanitarian aid worker Alma Schlor with the Tucson Samaritans recovers a water bottle covered in camouflage material while leaving water in the desert during the Flood the Desert campaign.

Items left by migrants under a palo verde tree.

Volunteers with the Tucson Samaritans, from left, Denise Holley, Gail Kocourek and Alma Schlor, climb through a cattle fence to check a livestock watering trough, where Kocourek and Schlor found a 21-year-old Guatemalen man just two days before on June 29. Activists estimate that 150 migrants a year die in the Arizona section of the border with Mexico.

Carpet shoes left by a migrant near Three Points, Arizona. People wear these carpets over their shoes to avoid leaving tracks in the sand.

Volunteer Alma Schlor leaves rosaries for migrant people during the Flood the Desert campaign.

A water bottle abandoned by a migrant in a prickly pear cactus near Three Points, Arizona.

Volunteer Alma Schlor checks a watering hole for cattle for signs that migrants had been drinking from it during the Flood the Desert campaign in the desert surrounding Tucson, Arizona. Two days before, on June 29, Alma and a fellow volunteer, Gail Koucourek, found a 21-year-old Guatemalan man suffering from heat stroke and drinking from the dirty water.

Mayonnaise was among the items found by Tucson Samaritans volunteers during the Flood the Desert campaign.

Gail Koucerek uses her walking stick to check for scorpions before inspecting a found backpack for signs of identification during a water drop with the Tucson Samaritans for the Flood the Desert campaign.

A backpack left behind by a migrant and found by a volunteer with the Tucson Samaritans near Three Points, Arizona, southwest of Tucson.

Humanitarian volunteers with the Tucson Samaritans debrief at the home of Leesa Jacobson, left. The aid workers shared stories of what the different groups encountered and shared new information about an anti-migrant armed militia operating nearby.