The elected prosecutor needed a boost in the polls to help insure his re-election and pushed too hard for an indictment; counting on DW to waive his right to a speedy trial. It makes no sense for a defendant who is innocent to waive his right to a speedy trial and give the prosecution enough time to 'create' evidence or twist innocent events or facts into 'proof'. If DW committed this crime and is found 'not guilty', and later evidence proves it, the prosecutor's political career will be in ruins.
Especially if he/she is already a prisoner in jail and can't get bail. If they waived there right to a speedy trial they could be sitting there for a year or more.