People familiar with the autopsy report told the newspaper the bones broken in Epstein's neck included the hyoid bone, which is near the Adam's apple.
This sort of break can happen when a person hangs themselves or dies by strangulation, forensics experts told the Post.
Epstein, 66, was found dead in the special housing unit of the federal Metropolitan Correctional Center in New York on Saturday. He was in a cell by himself.
The multimillionaire hedge fund manager had been jailed since early last month, awaiting trial on federal charges accusing him of operating a sex trafficking ring from 2002 to 2005 at his Manhattan mansion and his Palm Beach estate in which he paid girls as young as 14 for sex. He pleaded not guilty to the charges.
Two prison staff members who'd been guarding the unit where Epstein died by apparent suicide failed to check on him that night for about three hours, The New York Times reported Tuesday, citing several law enforcement and prison officials with knowledge of the investigation.