Those documents can be found here. The firearm that Manuel Osorio Arellanes or the other redacted defendant was accused of possessing, a Romanian WASR-10/63 AK-47, serial number 1971CZ3775, was one of two Operation Fast and Furious firearms traced to the murder scene. (See p.46 of the Oversight Report) I may be mistaken as I'm going from memory here but I don't think either of these weapons had been tied conclusively to Agent Terry's murder before now. It has always been said they were at the scene but never used in his murder. If the court documents are accurate - and there is no reason to believe that they aren't - then the government is now saying a gunwalked AK was used to kill Agent Terry.
This is political dynamite! No wonder the Democrats are working so hard to blame the locals and exonerate Eric Holder.
UPDATE: In an article published last night, Dennis Wagner of the Arizona Republic says the second person indicted for the murder of Border Patrol Agent Brian Terry is Rito Osorio-Arellanes.
The U.S. District Court documents name Rito Osorio-Arellanes, 41, who is believed to be a brother of the only previously named defendant, Manuel Osorio-Arellanes.Wagner notes in his article that there is a third suspect who remains at large and who has not been identified.