At first I thought "maybe they got enough" but that's not really how prosecutors work, do they? You don't just wrap up and call it a day because you found some finger prints and a bloody rag. You'd probably want to question the guy whose fingerprints you found... especially if he said he wasn't there.
But either way, I don't think Barr will release the report. He was hired with a very specific job description, which was to not release the report and also to gently cup the presidents balls while he's sucking him off. So I expect a subpoena (I'm surprised they didn't issue one preemptively) followed by a lengthy court battle.