Professor Imwinkelried a signatory to amicus brief successfully challenging bitemark evidence

The Texas Court of Criminal Appeal in December set aside a 1987 murder conviction based on an amicus brief to which Professor Edward Imwinkelried contributed.

The conviction of Steven Chaney was based in large part on forensic odontological (bitemark) testimony. At trial, the prosecution presented forensic odontological testimony that Chaney was the source of a bitemark on the decedent's body and that there was only a "[o]ne to a million" chance that someone other than Chaney bit the decedent.

 In 2015, Texas amended its Code of Criminal Procedure to grant post-conviction relief when subsequent scientific research "contradicts scientific evidence relied on" at the previous trial. Chaney petitioned for relief under the amendment. A group of forensic scientists, statisticians and evidence scholars, including Professor Imwinkelried, filed an amicus relief supporting Chaney's petition. In their brief, the amici cited the empirical studies demonstrating that: (1) forensic odontologists cannot reliably individuate the source of a bitemark; and (2) there is no trustworthy basis for computing probabilities in bitemark cases.

Citing the amicus brief, the Texas Court of Criminal Appeals granted Chaney's petition in Ex parte Chaney, NO. WR-84,091-01 (Tex. Crim. App. Dec. 19, 2018). Citing Chaney, the court granted a stay of execution in another case in early January 2019.  One of the other signatories to the brief was Professor Paul Giannelli, Professor Imwinkelried's co-author on Scientific Evidence (5th ed. 2012).

In 2015, California adopted legislation similar to the Texas provision. The amici have revised their brief and submitted it in a pending California case.

Professor Imwinkelried is a world-renowned evidence expert who has published extensively in the field.