Reporting from Seattle A Mexican man with a history of illegally moving across the U.S. border has been indicted with several still-unnamed defendants in the slaying of U.S. Border Patrol Agent Brian Terry during a late-night encounter in a remote southern Arizona canyon. A federal grand jury indictment unsealed Friday charges Manuel Osorio-Arellanes, who was wounded in the confrontation, with second-degree murder, assault of a federal officer and other crimes stemming from the Dec. 14 incident. Authorities said several other suspects named in the indictment, including the man thought to have fired the shot that killed Terry, remain at large. The incident occurred when Terry and three other agents were patrolling the backcountry near Rio Rico, Ariz., about 13 miles north of the Nogales border crossing, and ran into a group of suspected bandits thought to be preying on illegal immigrants and drug smugglers, law enforcement officials have said. The indictment said the defendants were patrolling an area known as Mesquite Seep in single file, at least two of them carrying assault rifles at the "ready" position, when they encountered the Border Patrol agents. At least two of the defendants shot at the agents after the officers identified themselves as lawmen, the indictment alleges. "Today's indictment is an important step in this case, but it is only a first step to serving justice," Dennis K. Burke, U.S. attorney in Arizona, said in a statement. "This is an active, ongoing investigation that is making more and more progress every day." Osorio-Arellanes, who has been in custody on immigration charges since the incident, has pleaded not guilty. Border Patrol death: Mexican charged in U.S. agent's slaying - latimes.com Just another example of Mexico's war on America!