By Brandon Lowrey ANGELUS OAKS, Calif., Feb 13 (Reuters) - Rick Heltebrake was driving his pickup truck through a remote campground in the mountains east of Los Angeles on Tuesday, with his dog at his side, when a man emerged from a roadside snowbank and aimed an assault-style rifle at him. Heltebrake, 61, pulled over and immediately recognized the hulking, armed man as the fugitive ex-cop wanted in a killing spree, Christopher Dorner, whose face had been plastered on billboards, newspapers and televisions for nearly a week.