ALEXANDRA ULMER A U.S. police officer killed in a mass shooting at a Colorado supermarket on Monday had seven children and had been looking for a new job in order to protect his family, his father said. The shooting in Boulder, Colorado, left nine other people dead while a suspect injured in the violence was arrested, authorities told a news conference late on Monday. Officer Eric Talley was the first on the scene, Boulder Police Chief Maris Herold said, lauding his intervention as "heroic." Talley, 51, had joined the police just over a decade ago and had been looking to…