Because there’s nothing new to report until the trial. News stories get cold fast.
There is plenty to report on new developments in the case, but the media does not want to report it. Many whites have been beaten by racist blacks in the name of Trayvon. In Norfolk two white reporters were beaten by a mob of black racists and their own newspaper refused to cover the attack.
The racism connected to this case since they broke the story, has been in direct reaction to their racist smearing of “white” Zimmerman. They have a lot of innocent blood on their paws.