The prosecution can only hurt itself by revealing all of this heresay through the news media. The defense can claim that any potential jury has been tainted and seek to throw out important pieces of the prosecution's case. Whether that works or not is another matter, of course. At the end of the day, Padilla will (hopefully) have a normal trial and be convicted or freed on the merits of that trial. It's deeply unclear, however, whether somebody accused of being an Al Qaeda terrorist can get a fair trial anywhere in the U.S., regardless of the pre-trial publicity or lack thereof.