DNA testing won Anthony Wright a new trial, and on Wednesday a DNA analyst began explaining the results of those tests to the Philadelphia jury that will decide if Wright is guilty of the 1991 rape and murder of a 77-year-old Nicetown woman.

Wright, 44, served 21 years of a life prison term after a Common Pleas Court jury convicted him in 1993 for the slaying of Louise Talley.

The prosecution's case was built on Wright's eight-page confession to the crimes, blood-spotted clothing that detectives said they found in Wright's bedroom where he told them it would be, and a teenager who told police he saw Wright wearing a black-and-red Chicago Bulls sweatshirt and pacing in front of Talley's house.

Wright has always maintained that the confession was coerced, and on Wednesday DNA expert Jennifer Smith told the jury that Wright's DNA was on none of the physical evidence found in 1991.

Smith said DNA samples recovered on inside surfaces - crotch and seat, elbows, and knees - of a black-and-red Chicago Bulls sweatshirt, blue jeans, and pair of black FILA sneakers show that they were worn only by Talley herself.

Wright was only a "potential contributor" of DNA found on the waistband of the jeans, Smith said. But defense and prosecution lawyers agree that likely occurred in Wright's 1993 trial when the prosecutor asked him to hold up the jeans for the jury.

Questioned by defense attorney Peter Neufeld, Smith said she took 107 cuttings or swabs from exterior and interior surfaces of the clothing and tested them for DNA.

All of the blood spots, Smith testified, came from Talley. DNA from the 107 samples came from either Talley or from Ronnie Byrd, a former Philadelphia crack dealer who died in a South Carolina prison in 2013 at age 62.

"They were unique samples," Smith added.

Until three years ago, police and prosecutors maintained that Wright was the sole person responsible for Talley's rape and murder. Then, Wright's lawyers, working with the Innocence Project of New York, persuaded a judge to let them use sophisticated DNA testing to reanalyze the physical evidence from 1991.

A first round of testing proved that Byrd - not Wright - was the source of semen found in Talley's body. In 2014, the District Attorney's Office agreed to a new trial.

In the retrial, Assistant District Attorney Bridget Kirn - again relying on Wright's 1991 statement - has argued that Wright sexually assaulted Talley but could not ejaculate. Kirn said the evidence would prove that Wright fatally stabbed Talley.

Manuel Santiago, a retired police homicide detective, has already testified and insisted that Wright's statement was voluntary and not coerced.

Last week, the teenager who said he saw Wright wearing the Chicago Bulls sweatshirt recanted his 1991 statement, telling the jury of seven women and five men that he never spoke to police.

Smith formerly was an analyst with the private forensic testing firm Bode Cellmark Forensics in Lorton, Va., which the Innocence Project hired to do the recent DNA testing.

After the Philadelphia Police Department's own DNA analysts confirmed Bode Cellmark's finding about the semen, the Virginia firm continued DNA testing of the 1991 clothing. The District Attorney's Office was granted permission to suggest additional tests done by Philadelphia Police DNA analysts on the clothing.

When the trial resumes Thursday, Kirn is expected to continue questioning Smith about the procedures she used in her DNA testing.

On Wednesday, Kirn focused on several DNA samples from the clothing that Smith said were inconclusive when tested against Wright's DNA sample.

"That means you can't exclude Anthony Wright as the source for that sample, doesn't it?" asked Kirn.

"That's not a fair question," Smith replied. "Inconclusive means I can't exclude him and I can't include him."

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