Former Norwalk Assemblyman Bruce Young testified before a federal grand jury in the ongoing investigation surrounding the political activities of former Anaheim fireworks manufacturer W. Patrick Moriarty. Young, convicted of five counts of mail fraud for failure to report the source of contributions he accepted from Moriarty, could provide important evidence against other government officials who are targets of the probe. Prosecutors declined to discuss Young's testimony. Now a Sacramento lobbyist, Young faces an 18-month prison sentence for his conviction, which is on appeal. He had been scheduled to appear before the grand jury last month, but canceled his appearance when he was admitted to an Oakland hospital for chest pains.