It never became a top priority for the Swedish state. But since he fled to the Ecuadorian embassy the investigation just dragged on. This was never a high priority case other than for the press. And as soon as he could be inteterogated the investigation was closed.
He is and has been mistreated in may ways, but the accusations of sexual assault in Sweden was not part of some US lead conspiracy against him.
The public prosecutor can press charges, which is what happened here. They don't for a boatload of would be cases. With Assange, they did, which is not exactly true to form.
