Hundreds of inmates in prisons across the US have been exonerated and freed because of DNA evidence that proved their innocence.

And 48 states now give inmates some degree of access to DNA evidence that might not have been available at the time of their convictions.
 
But other 'science' that puts thousands behind bars is also coming under scrutiny. Much of what was regarded as unassailable – hair analysis, arson investigation conclusions, eye-witness identification – is now being seen as fallible.

In this documentary we look at several cases in the death-penalty-prone states of Texas and Oklahoma where new technology is making a difference.

We talk to a recently released Oklahoma man, Curtis McCarty, who served 22 years for a murder he did not commit, originally convicted on the basis of erroneous testimony by a forensic lab worker.

We also meet Hank Skinner, who is still scheduled for execution in Texas. He is trying to get access to the DNA he says will exonerate him. He took his case all the way up to the Supreme Court, and in October, the justices announced that they will decide whether state officials can be forced to turn over that DNA evidence.

We also compare the cases of two men convicted at about the same time for arson/murder on the basis of the same "junk arson science". One, Todd Willingham, was executed, and the other, Ernest Willis, was released.

And we meet Craig Watkins, the new African-American district attorney of Dallas, Texas, who is changing the old 'presumed guilty' style of his office.

American Justice: Fatal Flaws can be seen from Saturday, October 16, at the following times GMT: Saturday: 0830, 1900; Sunday: 0030, 1230, Monday: 1430.

Source: Al Jazeera