WASHINGTON (AP) — For two decades, U.S. Rep. Henry Cuellar has stood out as a moderate Democrat along the Texas-Mexico border, bucking his party at times over guns and immigration while seldom facing a tough reelection.

But a federal indictment accusing Cuellar of federal conspiracy and bribery charges is putting the Laredo native who was first elected in 2004 in a different spotlight. Cuellar, 68, and his wife, Imelda, 67, were taken into custody Friday in connection with a U.S. Department of Justice probe into the couple’s ties to the former Soviet republic of Azerbaijan.

The congressman professed his innocence after the indictment was revealed and vowed to continue his bid for an 11th term in November, saying, “Everything I have done in Congress has been to serve the people of South Texas.”

The Cuellars are accused of accepting nearly $600,000 in bribes from an Azerbaijan-controlled energy company and a bank in Mexico. In exchange, Cuellar allegedly agreed to advance those entities’ interests in the U.S.