There likely won’t be any blockbuster revelations from the long-overdue Department of Justice investigation into former South Florida federal prosecutor Alex Acosta’s misbegotten deal with hedge-fund manager Jeffrey Epstein, accused of sexually molesting more than 100 young girls over decade ago.

First, DOJ’s own Office of Professional Responsibility will conduct the probe. It will amount to an internal investigation. And as reported by Miami Herald reporter Julie Brown, OPR is extremely secretive, and its findings rarely are made public. But this case warrants a spotlight and transparency.

Second, it’s unlikely that the investigation will result in a finding that Acosta engaged in “professional misconduct” in giving Epstein a controversial plea deal that netted him short stay in jail — and a cushy one, at that. Professional misconduct is a high bar to clear, as it should be. Many decisions, though lacking in wisdom or misguided, can still fall within the permissible standard of prosecutorial discretion. The public deserves answers, not a witch hunt. Still, just because something can be done within the broad discretion afforded a U.S. attorney, doesn’t mean that it is the right thing to do.

Third, and most important, OPR has no power to subpeona witnesses. Epstein’s alleged victims, again, will not have a chance to tell their own stories of sexual intimidation and abuse. Nor will Epstein’s powerful friends or his enablers be heard from. So it’s possible that, again, we won’t get the full story.

These three hindrances aside, however, the investigation is a welcome development. The stench of this horrible plea deal that has denied alleged victims even a hint of justice has lingered for too long. And Epstein has yet to be called to account.

The Herald’s prodigious investigation in this case uncovered how Epstein assembled “a large, cult-like network of underage girls — with the help of young female recruiters — to coerce into performing sex acts behind the walls of his opulent waterfront mansion as often as three times a day.” The glitzy surroundings, no doubt, initially dazzling the young and trouble girls. But the pressure the girls were under to perform was equally intimidating.

When the set-up was discovered, Acosta, who was the U.S. attorney based in Miami, signed off on a lenient plea deal — crafted mainly by Epstein’s lawyers. In 2007, Epstein pleaded guilty to charges of prostitution — not sexual assault — and served 13 months in a county jail, able to leave every day to go to his office. The girls never were told a thing about the deal.

Acosta now is U.S. labor secretary; Epstein is living large. The accusers? They’ve moved on with their lives to various degrees. But they have yet to be made whole.

The investigation into this egregious case needs to be kicked into a higher gear. It demands an inquiry that answers the question: What should have been done — that wasn’t done — to safeguard the rights and interests of the minor victims?

Both the U.S. inspector general and Congress, specifically the House Judiciary Committee, would be better vehicles to getting closer to the truth, making findings and recommendations to change policies to prevent such dubious deals in the future. OPR can’t do this.

First, however, the Senate needs to pass the Inspector General Access Act of 2017. This would give DOJ Inspector General Michael Horowitz the authority to investigate the Acosta/Epstein case. This technical obstacle should not be allowed to block the path to long-delayed justice.