The sheriffs of El Paso and Hudspeth counties are expected to testify today before a congressional subcommittee in Washington, D.C., about the standoff last month near Sierra Blanca in which U.S. officers squared off with armed drug smugglers -- some of whom were dressed as Mexican soldiers. The sheriffs were invited to testify by Rep. Michael McCaul, R-Texas, Chairman of the Homeland Security Committee's Subcommittee on Investigations, who initiated an investigation following the standoff.Sheriff Leo Samaniego of El Paso is scheduled to speak as Vice Chairman of the Texas Border Sheriff's Coalition, which stands to gain $34 million if an immigration bill circulating the Senate passes, he said.