Please see the bottom of story for update

EXCLUSIVE: United Nations peacekeeping investigators looking into alleged sex crimes in the Central African Republic (CAR) have asked under-age girls if they were prostitutes and taken at least one photo of an alleged victim naked as evidence, according to an independent official with direct knowledge of the cases, Fox News has learned.

In one case, “the investigators thought that taking a photo of the [under-age] naked victim was enough of a medical examination” to determine the girl's age, according to Francoise Bouchet-Saulnier, a legal director of Medicins Sans Frontieres (MSF), a humanitarian organization that has carried out formal medical examinations of six alleged rape victims in CAR, including four U.N. cases, since January 2014.

Bouchet-Saulnier told Fox News that a U.N. investigator asked an alleged victim whether she had, in fact, been engaged in prostitution, “as if not knowing that the consent of a [very under-age person] was not legally valid.”

All of the MSF medical examinations involved under-age residents of the Central African Republic (CAR), aged from 12 to 15.

U.N. investigations of sexual abuse, along with any other alleged crimes, are carried out with the participation of the mission on the ground in CAR-- known as MINUSCA-- meaning they may have ties with those under investigation.

They are part of the U.N.’s overall deference to countries that contribute troops and police to U.N. peacekeeping missions and that maintain a monopoly on punishment—or non-punishment-- of any offenders ultimately judged guilty of sexual crimes.

The U.N. is currently investigating eleven different cases of alleged sexual exploitation and abuse—including rape—on the part of U.N. military and police forces in the battered CAR , with some cases going back to 2014, and no definitive conclusions to any of them.

The overall number includes two sets of rape charges arising from an Aug. 2 U.N. raid in the capital of Bangui, including a combined trio of new allegations that the U.N. revealed earlier this week--but most date back months, including some that surfaced not long after the U.N. force known as MINUSCA was formally established on CAR soil in mid-September 2014.

In at least three cases earlier this spring and summer, the U.N. has not even heard back from countries that provided troops or police charged with such offenses, to tell the world organization whether they intend to carry out their own investigation of the allegations—a necessary first step prior to any U.N. probe. U.N. procedures set a 10-working-day deadline for the response.

In one of those cases, according to the U.N.,  the troop-providing country asked for a few days of grace before replying; in another, even though the country has not replied, a national investigation by the troop-provider is ongoing—and in the third, the deadline was reached on Aug. 21, and the U.N. says it now intends to investigate on its own.

The still-undetermined results of all of the probes mean that there has not been a definitive finding of guilt or innocence against any U.N. peacekeeper suspected of the offenses—and can mean continuing uncertainty, terror and cynicism among the alleged victims, as well as among all those who know of them.

(In one CAR case, involving a member of a U.N. police force, the alleged offender has returned to his native country, “at the request of the police-contributing country,” a U.N. official told Fox News.)

The U.N.’s procedures—and what critics call a continuing “culture of impunity” among members of peacekeeping missions on the ground in 16 areas around the world—are leading to a rising clamor for dramatic reform of the U.N.’s peacekeeping justice system.

The uproar -- refueled by accusations of a U.N. peacekeeper rape of a 12-year-old girl on Aug. 2 -- led U.N. Secretary Ban Ki-moon to ask for the resignation of his special envoy and head of MINUSCA, General Babacar Gaye, though the actual troop commanders in CAR, provided by contributing countries, were not sanctioned. 

 An additional trio of alleged victims this week added their own accusations of rape during the Aug. 2 incident.

The stream of charges have further fueled accusations that the world organization is more interested in protecting alleged offenders than the often starving and vulnerable children and adults who fall victim to sex crimes.

Among the vocally outraged is a U.N. non-government organization, AIDS-Free World, which declared after the new revelations of U.N. sexual abuse revelations this week that “It’s time to abandon foot-dragging protocols that give the advantage to the predators.” 

The main poster child for that view is a U.N. official named Anders Kompass who last year blew the whistle on testimony of rape against French and African non-U.N. peacekeepers operating in CAR and is being investigated for violating protocols governing the confidentiality of victim testimony gathered by U.N. investigators. 

Ban has named a three-person “independent, external review” to examine the Kompass case as well as “any shortcomings in existing procedures covering serious crimes by United Nations and related personnel.” The panel is due to report next month. But a U.N. investigation of Kompass is continuing separately. 

Ban’s panelists could well start their review with the minimum ten-day waiting period that the U.N. offers after it refers news of a sex crime charge to the offender’s troop-providing country before starting any probe of its own.

The panel also needs to consider something further noted by MSF’s Bouchet-Saulnier: “What remains really at stake is basic assistance for victims. We need to relocate them. If there is no protection or assistance for the victims, they will not take the risk of notifying anyone of abuse.”

Moreover, many of the worst abused are often “starving. They may feel they have no alternative” to acquiescing in return for food and other favors, which feeds the narrative of prostitution.

What is needed above all, she declared are “best practices” that are “not just for the protection of the victims, but administrative procedures to protect the integrity of the institution.”

“A lot of people do theory on these cases,” she noted. “Not a lot of them are involved in practice.”

UPDATE: On Aug. 24, three days after this article was published, a spokesman for Medicins Sans Frontieres emailed Fox News to “clarify” that “the photo referenced  in the article was never taken. It was requested by persons taking part in the investigation during their meeting with MSF and the minor. MSF medical personnel refused the request.”

Two days earlier, on Aug. 22—a full day after this article was originally published-- the same MSF spokesman had emailed  Fox News on behalf  of Francoise Bouchet-Saulnier, to say “she wanted to make clear that the investigators thought that a photo was enough of an examination to assess the age of the victim (rather than to determine whether a rape had occurred, as the partial quote implies).” No mention was made at that time or previously that the photo did not exist.

George Russell is editor-at-large of Fox News and can be found on Twitter: @GeorgeRussell or on Facebook.com/George Russell