By KEVIN McGILL and MELINDA DESLATTE, Associated Press OPELOUSAS, Louisiana (AP) — Authorities said he had no known criminal record. A friend described him as an introverted animal lover who showed no animosity toward any race, and a talented, if frustrated heavy metal guitar player and singer. A fellow musician called him "a really sweet guy." But Holden Matthews, the white, 21-year-old son of a Louisiana