The Innocence Project says the linking of Delphi murders suspect Richard Allen’s gun to the killings of two teenagers “is not settled science.”

The forensic examination of tool mark analysis on an unfired 40-caliber bullet found between Abby Williams and Libby German was what led to his arrest.

The Innocence Project’s Senior staff attorney Tania Brief says the research on tool mark analysis is flawed and they have exonerated 375 people who were wrongfully convicted in its 30 years.