Correspondent Erin Moriarty looks at how advances in DNA technology might help solve one of the nation's most heartbreaking cold cases: The Yogurt Shop Murders in Austin, Texas. On Dec. 6, 1991, four teenager girls - 17-year-old Eliza Thomas, 13-year-old Amy Ayers, and two sisters, 17-year-old Jennifer Harbison and 15-year-old Sarah Harbison - were found gagged, tied up with their own clothing, and shot in the head in a yogurt shop, which was then set on fire. Eliza and Jennifer worked at the shop and were closing up for the night, and Sarah and Amy had met them there to head home together. Gunshot wounds revealed two different types of guns were used, but there was little other evidence at the scene, and the fire complicated the early investigation. The case is still unsolved.
—CBS 48 Hours