(CN) – For many victims, last week’s incarceration of sex offender Jeffrey Epstein represents belated justice after more than a decade of impunity and governmental complicity.

Beneath that gloomy surface, however, an even darker picture emerges: federal prosecutions of those who trafficked children for sex dropped 26.7% over the last year.

The startling numbers appeared Tuesday in a report from the Transactional Records Access Clearinghouse at Syracuse University.

“If the present pace of such prosecutions continues, the fiscal 2019 total will be 162, compared to 221 last year,” TRAC’s report states.

The Obama administration dramatically ramped up such prosecutions, climbing threefold from 85 cases in 2009, the year the 44th president took office, to more than 260 during his final year in the White House.

While those prosecutions held steady in the first year under President Donald Trump, TRAC’s analysis of Justice Department data says they have taken a dramatic plunge every year since.

“Compared to five years ago, the estimate of FY 2019 prosecutions of this type is down 32.2 percent, from 239,” the study says. “However, prosecutions over the past year are still much higher than they were ten years ago, up 90.6 percent from the 85 reported in 2009.”

TRAC obtained the data under the Freedom of Information Act.

The Southern District of New York, where Epstein was indicted last week, is tied with the Southern District of Texas as the most active pursuers of accused child sex-traffickers.

The Southern District of Florida, where Trump’s former Labor Secretary Alex Acosta let Epstein sign a 2008 nonprosecution agreement that shelved a 53-page indictment, does not even crack the top 10.

Reporting by the Miami Herald revealed that the plea deal immunized Epstein’s suspected co-conspirators from prosecution and allowed the tycoon to serve out a 13-month sentence for state-level prostitution charges in a county jail. Epstein took advantage of Florida’s work-release program six out of seven days a week.

Before criticism over the deal ended his tenure, Acosta pushed policies at the Department of Labor that pushed to divert resources from the mission of combating human trafficking. TRAC notes that individual U.S. attorneys have discretion over which cases to bring, but that prosecutors have increasingly declined referrals of cases involving child sex trafficking.

“When all referrals for federal prosecution for sex trafficking of children are examined, U.S. attorneys have generally turned down slightly more than half,” the study states. “In the last full year of the Obama Administration, federal prosecutors prosecuted 49 percent of these referrals. This percentage has been slipping since: during FY 2017 it was 46 percent and in FY 2018 it was 42 percent. So far in this fiscal year, Justice Department records show that the rate has fallen to 39 percent.”

The Justice Department did not immediately return a request for comment.

In a telephone interview, a former federal prosecutor whose experience included numerous sex-trafficking cases argued that TRAC’s listing of cases filed, rather than the number of defendants, may have distorted the numbers. TRAC did not immediately respond to a press inquiry about this methodology.

Still, the former prosecutor emphasized, the Trump administration’s antagonism to an immigrant visa program meant to protect sex-trafficking survivors could put anti-trafficking enforcement in jeopardy.

“In order to make these cases, you need the victims to be willing to appear as witnesses, that willingness is provided because these women see a path to a better life by cooperating with the U.S. government,” said the ex-prosecutor, who requested anonymity to discuss the views of career Justice Department officials.

First issued in the year 2003, the T-visa program was designed to provide sex-trafficking survivors four years of legal status, food stamps, job training and a pathway for their families to immigrate to the United States.

Such protections had been crucial to recruit witnesses against sex traffickers, who may be waiting to kill victims and their loved ones in their countries of origin.

“If all they see is death, they will stop cooperating,” the prosecutor said, referring to the witnesses.

For the prosecutor, such a Sophie’s choice was not an abstraction.

“I have specific memories of specific girls and women who were petrified that their families would be killed if they turned up on the witness stand,” the prosecutor said, emphasizing the need to make them feel protected. “That is the key to having witnesses: No witness, no cases.”

Before his resignation, Acosta’s Labor Department threw up hurdles to limit authority to certify visas and proposed an 80% budget cut to the International Labor Affairs Bureau, charged with combating human trafficking and child labor domestically and internationally.

House Democrats drafted a proposal on May 15 that would expand the program’s funding from $68 million to $122 million.