Charles Ellicott Commentary 2 Samuel 13:30

"And it came to pass, while they were in the way, that the tidings came to David, saying, Absalom hath slain all the king`s sons, and there is not one of them left." — 2 Samuel 13:30 (ASV)

There is not one of them left. —The story of this exaggerated report, so true to life, indicates contemporaneous authorship.