I don't think the jury told the judge that they won't be able to reach a verdict. On courttv they said they think the judge may have been told that one of the jurors doesn't want to participate in the deliberation process. Maybe it's the juror that never takes notes, picks his nails and doesn't listen? Then the judge read an instruction on their duties as jurors.
In any case the prosecutors sure proved beyond a resonable doubt (some here apparently expect beyond any doubt -- which is absurd) and did a good job. There is the timeline and there is the place where Scott went "fishing."