A man accused of assaulting a nine-year-old girl cannot be taken to court because police have lost vital evidence tapes .
Prosecutors said that the man, from Clifton, told police he attacked the child – and the recordings of that conversation were going to be presented in court by the Crown Prosecution Service.
But police have admitted that the video of the interview have gone missing and cannot be found.
Relatives of the girl contacted the Post after receiving a letter from the CPS saying it had "no alternative" but to drop the case as there was not "a realistic prospect of conviction" without the tapes.
Nottinghamshire Police have now launched an investigation into the loss, promising that "robust" action will be taken.
But the family, who cannot be identified by law, want to be sure that whoever is responsible is held to account.
"She is the child, she is the vulnerable one, the police should be looking after her," they told the Post.
"It is so unjust for the evidence to disappear.
"The police need to be accountable, even more so because this offence is against a young child."
The letter told the family that the accused man admitted, in a police interview, that he had assaulted the child.
It said the CPS requested the video as evidence for a trial which was set to take place this month.
"Unfortunately, we have been told by the police that the master tape and the working copy of the tape are missing and that they are not able to locate them," it said.
"Without this evidence, we are not able to prosecute the case."
A CPS spokesman said: "We can confirm we required tapes from the defendant's police interview to prove the case but were told by the officer in the case that they were not available.
"Without this material, there was insufficient evidence to proceed, so the case was stopped."
A spokesman for Nottinghamshire Police said the decision to stop the case would form part of an investigation by the force's professional standards directorate. He added: "Our officers and staff are held to the highest standards of professionalism and if the investigation shows that we have fallen short of these standards, robust, appropriate action will be taken.
"We have apologised to the family for the distress this incident has caused and we would like to reassure the public that every precaution will be taken to ensure there is no repeat in the future."
The force also said that, as of October 2015, it had moved to a digital system "removing the reliance on physical media such as tapes and DVDs" and ensuring all interviews were "recorded in digital format and securely, centrally stored"
But for the family, this is too little, too late.
"We are so angry, as she has been so wronged," they said. "If this is allowed to happened to [this child], who else could it have happened to?"