"48 Hours" can exclusively report there has been a huge break in the 1991 murders of four teenage girls in a Texas yogurt shop.

Old-fashioned detective work and advances in forensic science led to the identification of a suspect in the killings of four teenagers in Austin, Texas, in 1991, officials said.

For years, the unsolved killings of four teenage girls in an Austin yogurt shop in 1991 haunted investigators in the Texas capital. Two men were charged and convicted, only to have DNA evidence exonerate them, leaving the brutal deaths -- in which the girls were bound, gagged and shot before the building was set on fire -- an enduring mystery.