The Shadow Wolves, an elite Tohono O'odham Nation-based border patrol group, could expand under Gallego's bill.

On Wednesday, the Senate Homeland Security and Governmental Affairs Committee unanimously advanced the Shadow Wolves Improvement Act, a bipartisan bill introduced by U.S. Sen. Ruben Gallego (D-AZ).

Scout, a retired Homeland Security Investigations Supervisory Tactical Officer who led the Shadow Wolves unit along the ...