PHILADELPHIA (CBS) — It was another day of testimony Tuesday in the trial of Edward Archer, accused of shooting a Philadelphia Police officer Jesse Hartnett, and even a shake-up among the women and men who will decide the defendant’s fate.

Prosecutors focused on physical evidence they say was found at or near the scene where Hartnett was attacked.

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Prosecutors then called to the stand experts on forensics, ballistics and DNA analyst who testified that the white garb recovered near the crime scene contained DNA that was likely Archer’s.

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But witnesses told the court that the gun  could not be conclusively linked to the defendant, a point Archer’s lawyers pressed, arguing that DNA from crime scene investigators could have tainted the evidence.

Ahead of closing arguments, planned for Thursday, prosecutors are expected to play the videotaped statement Archer made to detectives, and will call a few additional witnesses. Then, it’s the defense’s turn.

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One juror has been replaced by an alternate, but no reason was given. There’s a gag order in place.