A surge in the number of volunteers fanning out across Arizona’s southern deserts to aid illegal immigrants is expected this summer. The increase comes despite the ongoing prosecution of two volunteers arrested last summer on federal charges they intentionally conspired to transport illegal entrants, leaders of illegal immigrant aid groups said. Shanti A. Sellz and Daniel M. Strauss, both 24, were arrested as they drove illegal entrants to a clinic on July 9 and face trial in October. Leaders of two faith-based groups, No More Deaths and Samaritan Patrol, say they’ve signed up hundreds of volunteers to deliver food, water and medical aid to migrants illegally walking into the country from Mexico. No More Deaths alone has 500 registered volunteers, up from 300 last summer. A third group, Humane Borders, puts water tanks in areas frequented by illegal migrants. The groups are trying to reach an agreement with the U.S. Border Patrol spelling out legal ways they can provide humanitarian aid to illegal migrants. The biggest issue is what to do when volunteers come across migrants they believe need immediate medical attention, the same situation that Sellz and Strauss contend led to their arrests. […]