In grand jury transcripts released last week, Cogburn stated that he may have violated Melissa Huckaby's Miranda rights just minutes after he told her she was arrested for the kidnapping and murder of Sandra Cantu.
Cogburn told prosecutors that he deleted an audio recording of their exchange. He says police do not have a firm policy about booking audio recordings into evidence.
Sheneman says the usual practice for such an investigation as Huckaby's is to book all such recordings into evidence.
Prosecutors say the development won't have any bearing on Huckaby's conviction or sentence.