Let me rearrange my quote then for your viewing pleasure, since you don't seem to understand what a confirmed sighting is.
If people don't call in that they saw Batman, then there's no confirmed sightings of the Batman. He's careful in the shadows. People could go 8 years without seeing him or 8 years and they think they see him once or twice but never tell a soul. Those are unconfirmed sightings. So to the knowledge of the police, yes...he has vanished that night to never return. Whether true or not.