Illinois murder case challenges longstanding ballistic tests

An Illinois man convicted of murder in 1994 could become the first person to be exonerated with the help of ballistic technology that has been used to put countless criminals behind bars.

Jurors convicted 51-year-old Patrick Pursley after an expert testified that marks on bullets and shell casings from the crime scene proved they could only have come from Pursley's gun. But technological advances have eroded confidence in ballistic experts. And the analyst who testified against Pursley is no longer so sure of his findings.

Pursley was granted a new trial in March after high-resolution images of the shell casings failed to find a definitive link to his gun. The case could pave a new path to challenge convictions. But only Illinois allows the use of ballistic imaging in appeals.