George Powell

George Powell III was convicted of armed robbery in 2009, and sentenced to 28 years in prison.

A jailhouse informant who claimed Powell confessed to him has recanted, admitting that everything he said was a lie.

The Texas Forensic Science Commission, a state agency that reinvestigated — and called into question — the key piece of evidence against Powell. Powell’s conviction hinged on a dispute over the height of the robber. The clerk at the 7-Eleven told police that the man wearing sunglasses and a ball cap who pointed a gun at her was about 5-foot-6. Powell, however, stands 6-foot-3.

To account for the discrepancy, prosecutors called to the stand an expert who examined video footage of the robber as he walked past the height-measurement strip next to the store exit. Michael Knox, introduced as an expert in forensic video analysis, testified that the 7-Eleven surveillance video showed a suspect at least 6-foot-1.

Although Knox “had never before estimated height based on photos or videos,” the appeal said, jurors convicted Powell of aggravated robbery.

In 2014, however, the Texas Forensic Science Commission voted to examine Knox’s determination as part of its role in helping judges, prosecutors and lawyers better use forensic evidence at trial.

The commission hired a national leader in forensic video analysis who — using industry-standard methods that Knox did not, including three-dimensional laser scanning and measurement scale analysis — determined that the robber was no taller than 5-foot-9, and could have been as short as 5-foot-6.

In its report on the Powell case, the commission concluded that Knox’s analysis was flawed and that his determination about the robber’s height was “unsupportable,” Powell’s appeals said.

Add it all up, defense lawyer Mike Ware said, and “this is an obvious case where they simply arrested and convicted the wrong man”.

Source: “Was the conviction of a Central Texas man built on bad science, lies?” American-Statesman, Nov. 18, 2016

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