Dw would have no case against the DA. Possibly against those whose affidavits that were used to get the indictment. Anything said in court cannot be the basis for a libel/defamation action. However the republishing of statements made in court can be the basis for a defamation/libel action if it not a 'fair' reporting of the testimony. In this case, DW would have a tough time prevailing in such an action. This is why prosecutors rarely talk to the press about the accused, other than to simply state that so-andso has been charged and pretty much leave the rest for the courtroom.
Malicious prosecution. Slander and obstruction of justice. Directed leaks are not covered by the same protection as statements in court.
It seems obvious to me that the DA did collude and conspire with members of LE to deprive MR. Westerfield of his right to swift and fair trial.