CENTENNIAL, Colo.—A former Nevada prison inmate was sentenced Tuesday to three consecutive life sentences in the long-unsolved 1984 hammer killings of three Colorado family members, including a 7-year-old girl, inside their suburban Denver home. Sixty-one-year-old Alex Ewing was convicted Aug. 6 of first-degree murder after a two-day trial in which prosecutors contended Ewing used a hammer and a knife to kill Bruce Bennett, 27, his wife, Debra, 26, and daughter Melissa in the Bennetts’ home. Melissa Bennett also was raped, prosecutors said. Another daughter, 3-year-old Vanessa, was beaten in the head with a hammer as were her parents and sister but survived the attack. Ewing is also charged with the hammer killing of Patricia Louise Smith, 50, in her home in suburban Lakewood about a week before the Aurora killings. Smith also was sexually assaulted. Ewing’s trial in that case is set for October. Arapahoe County District Court Judge Darren …