The conviction was overturned in 1995 by the Florida Supreme Court. The basis for the court’s ruling was the DNA testing technique. The original DNA test, which was one of the first in Florida was deemed unreliable.
Dan Krane is an expert on DNA evidence. He explains that “specific DNA testing used at that time was called “band-shifting.” The lab slightly tweaked the bands on a DNA test, which would have been on X-ray film in the 1990s.
“The court was saying, if the band-shifting didn’t occur, this wouldn’t be a good match,” Professor Krane said.
That evidence was removed from the case. And not allowed in the next trial. In 1997, with no DNA evidence allowed, a Florida jury found Hayes not-guilty at the retrial.
At the first trial, DNA tests required larger samples to be effective.” Like a blood stain the size of a quarter.” Professor Krane explained.
Now an accurate DNA test can be done on microscopic samples so small they can’t be seen with the naked eye. Only a few cells left by a suspect are enough. Even if decades have passed the cells don’t degenerate if they are kept in a cool, dark laboratory, he said.