Support workers have raised concerns about an “unbelievable” rise in the number of sexual crimes that have gone unsolved.
Police Scotland has admitted the number of rapes successfully detected between April and December last year fell by 30.7% compared with the same period in 2017.
And the rate of all detected sexual offences – including “sextortion”, cybercrime and grooming as well as physical assaults – has fallen by 7% as a whole.
Reports of sexual offences have also fallen by 18%.
Helen Hampton, acting manager of the Women’s Rape and Sexual Abuse Centre (WRASAC) in Dundee, suggested public confidence may be on the wane.
Speaking to Wave FM, Ms Hampton said: “I was a little bit unbelieving at first – it is shocking when you compare it with our own experience. We’re seeing increasing numbers of referrals to our organisation over the years and I don’t think it has ever gone down.”
In the three months between October and December last year, WRASAC supported 59 people, rising to 82 between January and March this year.
Ms Hampton added: “This may indicate that people are becoming less confident.
“Certainly some of the stories recently around the not proven verdict can leave women feeling very unconfident in the justice system and feeling that it’s hardly worth reporting the crime.
“The forensic process and examinations are really traumatising and that might put people off going through that process.
“I would hope that, given there is such a massive drop in detection, the police may do their own investigation.
“Seeing such a drop would have alarm bells ringing, I think.”
The figures were published by Police Scotland in a report given to Dundee’s community safety and public protection committee on Monday night.
Chief Superintendent Andrew Todd told concerned councillors: “This doesn’t indicate whether this is a good or a bad thing.
“Members will know that the numbers themselves don’t necessarily tell the true story.”
He added: “The detectable rate is lower than we expected.”
Detective Inspector Paul Boath, who has worked with victims of sexual abuse, revealed more than half of serious sexual offences reported were historical, making detection harder.
He said: “A large part of what we do is proactive, so if we become aware of someone that may have offended we will try to target perpetrators.
“People are gaining confidence in the police but this is an ever-changing area, more recently so. 55% of our serious offences are non-recent, happening more than 12 months ago.
“That can have an effect in terms of forensics and in the longer term those involved could be deceased.”
DI Boath added that social media companies can take up to a year to provide requested data, creating another obstacle when tackling cybercrime.
Councillor Alan Ross, convener of the committee, said: “We’ve known for some time about historic cases and we always encourage victims of historical abuse to come forward.”
But Lochee Labour councillor Charlie Malone called for further reassurance from the police that survivors are confident in coming forward.
He said: “I’m trying to get my head around this. What we’ve got to be reassured about is whether there are sufficient resources going into this.”
Ch Supt Todd said he will respond to Mr Malone’s concerns in due course.