A Sacramento jury today convicted Bobby Chiu of first-degree murder in his retrial over the Sept. 30, 2003, shooting death of Roberto Treadway outside McClatchy High School. Chiu, 22, was previously convicted in July 2005 for his role in what prosecutors described as the gang-motivated killing of the 15-year-old victim. The defendant's conviction was overturned last November when the California Third District Court of Appeal ruled that Sacramento Superior Court Judge Trena H.