(CNN) -- After days of insisting no formal complaints had been made about a teen gang calling themselves the "Roast Busters," New Zealand police now admit a 13-year-old girl made a rape allegation two years ago.
The girl, now 15, told 3 News on Wednesday that police officers asked her to re-enact the alleged rape using dolls during a videotaped interview in 2011. "It was traumatizing," she said.
The teenager repeated claims she said she'd made to police that she'd been raped by three boys from the "Roast Busters," a gang of teenagers whose online boasts about raping drunk underage girls caused outrage when they were exposed by local media this week.
For days, police said they were powerless to arrest the boys because none of their alleged victims had filed a formal statement. However, on Wednesday, they admitted the girl had made a formal complaint just weeks after the alleged attack.
"An investigation was launched and the complaint was thoroughly investigated," police said. "Whilst this was a distressing situation for the girl and her family, police determined that there was not sufficient evidence to bring a prosecution."
Waitematä Police District Commander Superintendent Bill Searle told 3 News on Thursday the decision not to prosecute the girl's alleged attackers would be reviewed in coming days.
He also said he'd be investigating why he wasn't told a formal complaint existed, adding there was a "little bit of disagreement" over what constituted a complaint.
"I was briefed there was no formal complaint. As far as I'm concerned what the lady said was a formal complaint. I'd like to apologize to her for any stress that this would have caused," he told 3 News.
He said he'd also be investigating the girl's claims she was asked a "lot of questions" about what she was wearing at the time of the attack. She said officers asked "why did you go out in this skirt?"
"It's not part of our policy, it's not part of our general practice to ask these sorts of questions," Searle said.
The country's police minister Anne Tolley has asked the Independent Police Conduct Authority (IPCA) to investigate the matter, particularly officers' questioning of the then 13-year-old alleged rape victim.
"Parents of young girls need to have confidence that complaints to police about sexual assault are investigated thoroughly and appropriately," she said in a statement.
Referring to the apparent confusion over whether a formal complaint had ever been filed, she said she was "disappointed" the full facts had not been divulged to her or the country's police commissioner.
"I don't expect to be told finer details of police operations. Police must remain independent of politicians. But I do expect police to be talking to each other," she said.
In a statement on Thursday, Police Commissioner Peter Marshall welcomed the independent review and said Waitemata District police remained "absolutely committed" to pursuing the matter.
"Prosecuting these matters before the court requires a very high threshold, and we only get one opportunity to get it right. This means it absolutely critical for victims that we have the strongest case possible, backed by the appropriate evidence before we can proceed."
Earlier this week, Searle told CNN they had been actively monitoring the group since the first alleged offense was committed in 2011. He said police interviewed two boys identified as the group's ringleaders again on Monday, but they hadn't admitted to anything that constitutes a criminal offense.
"The online claims themselves are not enough to warrant a prosecution," Searle said. "They might be morally inappropriate and unacceptable to us but we have to deal with evidence that would be admissible in a court of law and we haven't got to that stage yet."
Searle declined to confirm how many boys were involved in "Roast Busters," but said the two ringleaders led a "core group," as well as "an associated group."
The boys were attending at least two different schools at the time the alleged offenses were committed but all have since graduated, he said. It's believed they're now around 17 to 18 years old.
In a video posted to YouTube, two boys made no attempt to hide their faces as they told the camera: "We don't choose the roast, the roast chooses us ... They know what we're like; they know what they're in for."
They boasted of their exploits on a number of social media sites, including Ask.fm and Twitter, as well as a Facebook page which has since been shut down.
Searle said on Tuesday the boys had recently received death threats but had not requested police protection.