Regardless of whether or not you think these 2 were involved in Ms Kerchers murder; Unless they have new and compelling evidence with which to present to the court, the evidence they have would seem insufficient to convict. This same evidence has been tested to start with and then overturned on appeal, so it just seems a bit odd to me to bring a retrial with the same evidence.
And can you really have a meaningful trial if the accused do not even have to attend the trial? All very strange to me....