SIOUX FALLS -- Alexander Salgado, 26, who already pleaded guilty to murdering a 16-year-old Mitchell girl in 2009, proved difficult on the witness stand Wednesday morning during the Maricela Diaz murder trial. He took the stand shortly after 9 a.m. at the Minnehaha County Courthouse in Sioux Falls. Prior to him entering the courtroom, Judge Tim Bjorkman notified the court, jury and attorneys it was possible Salgado would be uncooperative. "He may be disruptive. If he is, he will be taken out while the jury remains seated," Bjorkman said.