The Doj believed them, but because Greenberg was a convicted felon for the same crime and other crimes, the Doj felt the jury could be left with doubt, the same with the girl, who now as an adult, a professional prostitute....the jury could be left with some doubt....
To be able even to bring charges under the guidelines, prosecutors must believe they will get a conviction from the jury beyond a reasonable doubt.
Though, the DOJ should explain itself on why it did not. People are saying it was Garland AGAIN, not wanting to look partisan, just like him not wanting to investigate trump for 1/6, until Congressional investigation results forced its hand.