If the adult was in middle of fighting with the little kid, and the little kid falls off his bike, your first assumption should be that the adult knocked him down. Once the adult denies, then you shouldn’t make any assumption and instead headline that they are trading accusations. Once the adult provides evidence but that evidence cannot be independently corroborated, that should be the headline. Once the evidence is corroborated, that should be the headline.
And that’s exactly what happened.