A volunteer with a group that helps immigrants in the Arizona desert will go to trial on Jan. 14 for charges of illegally harboring people in the U.S., according to federal court documents.

Scott Daniel Warren, a volunteer with aid group No More Death, was arrested on Jan. 18, 2018, in Ajo, Arizona at a site used for giving immigrants food, water, beds and clean clothes. Two migrants taking refuge at the site also were arrested.

Warren has pleaded not guilty to the charges.

MORE: The Wall: Untold stories, unintended consequences

His arrest took place just hours after No More Deaths unveiled a report accusing the Border Patrol of tampering with water stations left for migrants trekking through the harsh Arizona desert.

Warren's attorneys have argued to get the charges dropped, saying his actions to assist people in distress are rooted in his religious convictions.

"I am compelled to act. I am drawn to act. I have to act when someone is in need," Warren testified last May.

MORE:Arizona clergy call on activists to support migrants on U.S.-Mexico border

Federal prosecutors argued that the migrants were never in distress and therefore didn't need Warren's help.

A growing number of immigrants are dying in the Arizona desert, due mostly to soaring temperatures and lack of water.

Warren earned a doctorate in geography from Arizona State University, where he also works as an adjunct instructor. He wrote his dissertation on Ajo and the surrounding area and now lives in the community.

The trial will take place in U.S. District Court in Tucson.

Daniel González and Rafael Carranza contributed to this report.

READ MORE: