Arizona senators Jeff Flake and John McCain have written a letter to U.S. attorney general Eric Holder attempting to verify reports they have received indicating that the Department of Justice will halt prosecutions of all illegal immigrants in their state who are crossing the border for the first time, as well as repeat border crossers who do not have a history of criminal convictions.

Yuma County Sheriff Leon N. Wilmot first wrote to Flake in August regarding his concerns that Operation Streamline, a 2006 plan that he says has curtailed illegal-immigrant traffic, is being scaled back. Wilmot wrote that he learned that the United States Attorney’s Office for the District of Arizona will no longer prosecute first-time illegal border crossers. “From an outside perspective, this new guidance gives a strong impression that its sole purpose is to direct the UDA (undocumented alien) traffic and their criminal activity back to Yuma County,” Wilmot wrote. “This practice undermines everything that we have worked hard to achieve over the years for the citizens of Yuma County.”

In the Republican senators’ letter to Holder, Flake and McCain ask if such changes have been made and whether the impact of the possible changes on border security was considered. “The recent conditions in the Yuma Sector represent one of the few instances approaching a success with respect to border security,” the senators wrote in part. ”In addition, with Central American family units and unaccompanied minors presenting a multi-agency challenge, it would appear an inopportune time to potentially be removing tools from the border security toolbox.”