BRISTOL, Tenn. Authorities say a Bristol, Tennessee, police officer responding to a domestic dispute call was shot and killed last night. Officer Mark Vance arrived on the scene around 9-30. Sergeant Greg Leake said the 30-year-old was shot a short time after he entered the residence. Police did not elaborate on the domestic dispute, but 26-year-old Nickolus L. Johnson was arrested as the suspected shooter. Leake said charges are pending. According to police records, Johnson has a criminal history. In 1997, he was charged with malicious wounding in Bristol, Virginia and sentenced to six years in prison. Vance had been...