Jason Payne was wrongfully convicted of double homicide partly because of a flawed defense strategy.
The defense put all their strategy on the forensic evidence they presented to the jury. Although the defense's forensic case of Noel Martin and Ed Hueske was stronger, more compelling and made more sense than the prosecution's forensic case it wasn't strong enough to convince the jury of a homicide suicide. The defense didn't dig deep enough into the prosecution's forensic evidence to show that a double homicide was impossible to commit and just didn't add up.
When presenting opposing expert witnesses it is never a certainty which expert(s) the jury will believe. Instead of putting all one's eggs in a single basket the defense has to counter claims put on by a prosecution's circumstantial case. In this case the defense did not do that.
The defense put on very few witnesses in the circumstantial side of the case. The few witnesses they did call to testify were not asked enough questions and were asked the wrong questions. Had the circumstantial case been refutted by the defense it is very likely a different verdict might have been issued by the jury; the correct verdict of suicide homicide.