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Nearly 34 years after his 13-year-old sister died during the 1991 Austin, Texas, yogurt shop massacre, Shawn Ayers and his wife, Angie, have launched a national cold case effort while still seeking answers about the attack and whether an accomplice is out there.

Angie, along with Shawn, whose sister Amy was among four girls killed in the attack, have joined former prosecutors Mindy Montford and Anne Marie Schubert to establish the National Cold Case Center .

The decades-long search for answers in Amy’s case inspired the couple to help establish the nonprofit, which helps to fund unsolved homicide investigations , train investigators and support victims’ families.

Angie and Shawn Ayers have launched a national cold case effort while still seeking answers about the yogurt shop murders in Austin, Texas, where Shawn's sister was one of four victims.…