TESERO, Italy, Feb 20 : When the Varesco family headed off to watch the biathlon at the Winter Olympics on Wednesday they left their two-year-old Czechoslovakian wolfdog Nazgul locked in his kennel at home in Tesero. In their absence, Nazgul became the most unlikely star of the Milano Cortina Games after escaping from the house and wandering onto the nearby Olympic cross-country course before sprinting down the finishing straight alongside the skiers.  “We were on the train to Anterselva to watch the biathlon,” Alice Varesco told Reuters on Friday.  “We were three hours from home when friends started sending us videos. That was the panic moment. We realised we could not do anything.” For a few surreal seconds during the qualifying races, spectators thought a wolf had wandered onto the course.  Instead, it was Nazgul, lean and silver-grey, ears pricked, locking onto the skiers ahead of him and instinctively joining the chase.  He even appeared in an official photo finish image, which was how Alice and Ernesto Varesco ultimately confirmed it was their dog. “Concern, for …