HE is still out there.

This summer, on a Glasgow path overgrown by trees, a man first circled a woman and tried to lure her into some woods. Then he exposed himself and began masturbating.

His victim, deeply distressed, escaped. So – at least for now – has he.

That is because, weeks after his crime, the man remains at large. Police Scotland say they have “no positive line of inquiry”, their way of saying they are not pursuing any specific leads. Their investigation, carried out by specialist public protection detectives, “remains open”.

Officers do not doubt, insiders stress, the credibility and good faith of the victim and their only witness, a then 20-year-old student. She, however, does doubt them. So much so that in last week’s Herald on Sunday the woman, Caitie Mackay, waived her anonymity to express her hurt and frustration about both the crime and the way she felt it was handled by the police. Her story was powerfully told by her father, The Herald and Herald on Sunday writer-at-large Neil Mackay. Very few victims of sexual offences are able to share their perspective. Fewer still have the courage to do so under their own name.

Caitie said she had identified a suspect to the police but that this man had never been interviewed. Why? Because, she was told, he would be unfit to understand the process. Last week, we suggested the man had mental health issues. In fact, we can now report, he has serious learning difficulties.

She said the man was stalking her, turning up at her work, one of Glasgow’s biggest shopping malls. She did not feel safe. “Trying to get any form of justice or protection is pointless,” Caitie said. “I feel as if what happened to me simply does not matter. My faith in the police is destroyed.”

Last week, Mackay, profoundly worried about his daughter – and about the public interest issues he raised about the investigation of sex crimes – put a series of questions to the police. This week we can report how they responded.

Officers spoken to by The Herald have great sympathy and respect for Mackay and his daughter. Their perspective on the investigation, is, however, in some details, is at odds with that of the Mackay family.

So much so that some of their differences may have to be resolved by a complaints process already under way thanks to formal interest from a politician following our story last week.

Police, specifically, say they carried out an extensive investigation in to Caitie’s complaint – which is one of public indecency rather than “a sexual assault”, as we termed the offence in a headline last week.

They also say there is “insufficient evidence” to link the man with learning difficulties to the case.

And they say they have no record of any report of stalking against the man. The Mackays dispute this and are understood to be considering their own formal complaint against the police.

The officer in charge of investigating this case is Detective Superintendent Alwyn Bell. He leads Glasgow division’s team of public protection detectives, specialists in sex crimes. It was his unit, he explained, which took over the case shortly after Caitie reported it.

Bell said: “Following a report of a man having indecently exposed himself near to Darnley train station on July 20, officers spoke to the victim and carried out a number of inquiries including a full search of the area.

“The inquiry was then allocated to the dedicated Public Protection Unit within the division, and following a CCTV check and other inquiries, there was no further information available at that time to identify a suspect. However, the inquiry remained open.”

Bell said that efforts had been made to keep the victim updated on this investigation by phone but added that “officers were unsuccessful”. The detective, who has occupied senior public protection roles in both Glasgow and Edinburgh, also addressed – within serious legal limitations on what he can say – the concerns the Mackays had over the man identified by Caitie as her attacker.

He said: “On July 27, the victim made a further call to police reporting that she had seen the suspect within her workplace. Officers attended to speak to her and the suspect was identified by the victim as being the individual who had carried out the public indecency. “Inquiries were undertaken and, due to his behaviour, he was returned home to his parents. Officers then obtained medical advice regarding the suspect’s condition and it was made clear by a medical professional that he has significant learning difficulties, and therefore lacks the capacity to understand a police interview or the ramifications of his actions or conduct.”

The man is on Police Scotland’s vulnerable persons database or VPD. He has been the subject of some inquiries. However, the force, in a formal statement to The Herald on Sunday, said they currently do not have a positive line of inquiry in the case.

Bell added: “The inquiry into this incident remains open and we would ask anyone who has any information which may assist, to contact us.”

The story centres on some of the trickiest and most sensitive areas of police work: updating victims on live investigations and handling inquiries which touch on vulnerable people.

There can be legal, ethical and practical reasons why officers cannot share the full story of any live inquiry to complex, messy, human crimes with journalists, the relatives of adult victims and victims themselves. There can also be miscommunications and misunderstandings between police and those whose lives are affected by crime and its investigation.

The circumstances of this case now look likely to be settled by a formal independent process of complaints.

Police Scotland has faced complaints about such issues before, including those which have been upheld and those which have not been. Each such complaint, say insiders, offers a chance to learn lessons or get to the bottom of a dispute.

The force in recent years has also increasingly secured the trust of organisations which support victims of sex crimes. Whatever the outcome of formal concerns about the Mackay case, the force will be eager to rebuild trust among victims and their families. Differing perspectives on the course of the investigation aside, insiders stress they see Caitie as a good faith witness.

Senior officers in recent years have put huge public emphasis on a message that they want to hear reports of sexual offences. Last financial year they recorded nearly 11,000 such crimes, more than double the historic norm. Numbers continue to rise this year, early reports suggest. In 2016-17, there were 64 cases of public indecency, the kind of offence experienced by Caitie.

Somebody, police are sure, put Caitie through a terrifying ordeal on July 20. That somebody has not been caught. There have not been any reports of similar crimes in the area. However, the man who tormented Caitie may well have exposed himself to others. If you were one of those women, or have any information about who the man might be, contact Police Scotland.