Queensland detectives have privately told an alleged gang rape victim that evidence has been destroyed in a number of criminal cases including hers, crushing her hopes that all the attackers will be brought to justice.

Key points: An alleged rape victim recorded a detective admitting that evidence from her case had been destroyed

An alleged rape victim recorded a detective admitting that evidence from her case had been destroyed The woman said she was gang raped on her 21st birthday and the dress and underwear from the night of the attack were destroyed

The woman said she was gang raped on her 21st birthday and the dress and underwear from the night of the attack were destroyed Queensland Women's Legal Service say the incident is a breach of the state's Human Rights Act

The revelation comes from secret recordings and emails obtained by Brisbane woman Eve* as she pressed police for a fresh investigation two decades after reporting brutal assaults by a group of men on her 21st birthday.

Eve said last year a detective revealed that police had destroyed her dress, underwear and other potential sources of DNA taken during the initial investigation in 1995.

The disclosure left her reeling and suicidal, prompting her admission to a psychiatric hospital.

After Eve recovered, she documented information from police suggesting the destruction of her evidence was not an isolated case.

The ABC has obtained a recording Eve says she made of a meeting with another detective in November 2018.

"I know there was a process ... yeah ... probably within the last two or three years where there were things that were destroyed," the detective said on the covert recording.

"They were moving storage points ... there was things that have been destroyed not just in your case, in cases ...

"That was a decision that was made with ... with some things, that they have destroyed things and ... yeah."

In July 2018, Eve's counsellor raised her case with police on her behalf and told Eve that a detective had confirmed "much of the evidence ... is no longer in existence".

"As she has mentioned to you, no doubt, this makes reviewing the case difficult," the email read.

"[She] shared that it is her understanding that the evidence was stored in a facility that a System Commissioner gave permission to destroy.

"She made it clear that, while this is not the process that is adhered to in current times, she believes this action was taken in line with procedures at the time."

Eve pictured on the night of her 21st birthday in 1995, hours before she was allegedly gang raped by four men at a unit in West End. ( Supplied )

Eve, who had reported the attack within hours, said she had never withdrawn her complaint and the destruction of evidence was "not something I ever could have foreseen".

"That was really a devastating thing to be told... that was really like a punch in the stomach," she told the ABC.

"I came really close to ending my life.

"That was just something I couldn't get my head around. I still can't.

"All those swabs, everything that I went through hell for ... all the samples, everything in the hospital, the dress, everything they collected, just destroyed it all."

Eve said she was alarmed at "the thought that there are other people that have to go through this anguish".

Breach of the Human Rights Act

In a statement, police denied there was a "decision made to destroy evidence in contradiction of the Retention and Disposal Schedule", which requires records in sexual assault cases to be kept for 75 years.

"Relevant exhibits relating to sexual assaults, that are of evidentiary value, are kept in the case of unsolved sexual offences," a spokeswoman said.

She said police would "not comment on the specifics of the victim's matter as it is an ongoing investigation".

Eve's case, now with the police sexual crime group, hinges on a single remaining swab.

It contains two other DNA profiles — one of which has been identified through a match at another crime scene in 2006.

Eve's police investigation file, released under Right to Information laws, records testing only of a "high vaginal" swab and not for other samples in the rape kit or her dress and underwear.

That meant "the best I could hope for is to try a prosecution against one or maybe two of them and the rest of them just get to walk around freely," she said.

Queensland Women's Legal Service lawyer, Julie Sarkozi, said the police's loss of evidence was "not only concerning legally" but a breach of the state's new Human Rights Act.

"In my view, the fact that her private information was actually interfered with, without her knowledge and consent, would be a clear breach of Section 25 of the Human Rights Act," Ms Sarkozi said.

In her 2018 witness statement, Eve said she celebrated her 21st birthday at a restaurant in Brisbane's CBD with her family before joining a friend at the Gig nightclub.

She told police she left the club to get a taxi at 5am — alone, "very drunk" and affected by anti-anxiety medication — but was persuaded by a young man outside to accept a lift home.

She said he instead drove her to an apartment in West End where at least four other men were waiting and told her; "we are going to have our own party".

"That's when I realised I was in trouble and something terrible was going to happen," her statement said.

She describes a brutal, prolonged series of rapes in which she feared being killed by men who ignored her screams and treated her "like some kind of ragdoll for them to pass around".

"It's totally destroyed my life," Eve said.

"And the amount of shame and guilt and humiliation over that ... because I was constantly told, 'well, you were drunk, you did leave by yourself', and so it's just not something I've ever been able to get over.

"There's been many times I've tried to kill myself because it just got too overwhelming."

Eve was allegedly gang raped in 1995 and the alleged offenders have never been charged. ( ABC News: Lucas Hill )

DNA match years later

The investigation file reveals that within hours, Eve was at the Royal Women's Hospital sexual assault unit where medical examiners found "results consistent with the complaint".

Eve said an "appalling" police investigation began when two male detectives then took her straight back to West End in an unsuccessful bid to find the crime scene.

The file states she was "unable to identify the exact location of the offences" and there were "no suspects or witnesses".

She heard nothing more until March 2006, when the lead detective told her about a DNA match on one suspect.

Eve said she was reluctant to go to court to help prosecute just one offender.

But her file reveals that months later, police found the suspect and an associate who lived in the area at the time of the offence.

The associate volunteered a DNA sample and the names of two other friends from that time.

The file states the lead detective "indicated that further enquiries would be required with the complainant prior to making a decision in relation to this suspect".

But Eve said she was not contacted or told about the new leads, including that there was a second unidentified DNA profile on the swab.

She said she would have seized on "a chance to get some kind of resolution because it's not just one person".

In recent months, a new detective at the sexual crime group has made some progress.

She helped Eve identify a possible crime scene at West End, thanks in part to her description of a stair railing she tried to cling to before she was dragged into the apartment.

Last week, after the ABC contacted police about the case, the detective told Eve a police legal officer now believed there was sufficient evidence to prosecute one suspect.

But "the majority of these people will never have to ever answer for what they've done ... because the police didn't even bother to test the evidence and then destroyed everything", Eve said.

Ms Sarkozi said the case showed an "appalling lack of due process" by police.

"It concerns me that the actual investigation was handled so poorly, that not one person was charged for that offence, but over and above that it concerns me that the investigation [apparently involved] three days of concerted effort by the Queensland police and then nothing," she said.

"The victim was not informed about any progress in relation to the investigation of her complaint until 2016, and then again, nothing until she agitated under [Right to Information]."

Ms Sarkozi said it was "very common" for victims to be "left out in the wilderness" by police.

The Queensland Police Service (QPS) spokeswoman said the service was committed to "continually improving our response to investigating and dealing with victims who have experienced sexual assault or other trauma".

She also said QPS was committed to implementing recommendations from the Royal Commission into Institutional Responses to Child Sexual Abuse "in parallel with any new obligations under the Human Rights Act and the Charter of Human Rights".

* Not her real name