The police watchdog has upheld complaints that police failed to properly investigate a man's claims that he was sexually abused in foster care as a child.

The Police Investigations and Review Commissioner said Police Scotland should address failings in the treatment of Richard Tracey, who was a victim of physical abuse by his foster father, and a teacher in a residential school, and who also claimed he had been sexually abused by a family friend of his foster parents in the 1980s.

Having approached the police in 1993, an investigation was carried out, but his social work file was not obtained and key witnesses - including his foster siblings and the biological children of his foster parents George and Charlotte Tracey were not interviewed.

Richard Tracey made a fuller statement in 2002. At this point one of those who had abused him - a teacher at a residential school who beat him with a riding crop - was questioned and admitted the assault.

The case was passed to the procurator fiscal but thrown out of court because it was alleged Mr Tracey had delayed too long in reporting the incident - notwithstanding that he had previously reported the crimes against him nine years earlier.

In relation to the claims about abuse within the family, he was told his medical and social work records would not provide corroboration of his claims.

The PIRC review says it is not clear why this would be so, and a detective inspector assigned to the case had not properly explained to Richard why the records would not amount to corroboration in his view.

Comments from another officer involved, a Detective Constable, who told Richard he couldn't investigate further because his "bosses had said so" and advised him to "move on" from the childhood abuse, were also questioned. PIRC ordered Police Scotland to obtain a statement from this detective constable and reply to Richard about the appropriateness of the comments, if they were made.

When, belatedly, the family friend who was alleged to have abused Richard was questioned, he was shown poor quality photocopied photographs with details deliberately pixellated and asked to identify him.

Police later justified this action on the basis that the photographs were "in the format shown to you conform with fairness in court".

This is an inadequate explanation, Pirc ruled, and Police Scotland should provided Mr Tracey with a further response explaining why the photograph of his alleged abuser had been presented in this way.

Finally the force was instructed to give Mr Tracey an opportunity to make further representations, particularly in relation to a number of areas of his complaint that were completely ignored by investigating officers.

Police Scotland has now responded to the Pirc investigation in a letter to Mr Tracey from DCI John Hogg, from Ayrshire Division.

He wrote to Mr Tracey and said examining social work and medical records would not have provided sufficient corroboration for a sexual abuse case because eye witness testimony or reports from other victims would have been needed for the investigation to have been progressed.

He said the photograph of Mr Tracey's alleged abuser had been pixellated because it was of a different quality to police photos, adding "actions had to be taken to maintain fairness for court purposes, with a view to ensuring that all photographs had to be of equal visual quality to ensure that the photograph of the suspect does not stand out amongst the others."

He also claimed the detective Constable's comments to Mr Tracey about "moving on" and "bosses" dropping the case may have been "taken out of context" and the officer involved could not remember making them.

Overall, Mr Hogg says he is "satisfied... that my officers have done everything possible to address your complaint regarding the 1993 investigation not having been investigated properly through the reinvestigation and review that was conducted."

Mr Tracey said he was not happy with the response and added that he still did not understand why evidence from family members had not been considered. In a statement Elizabeth, Richard's foster sister, told the Herald she had been interviewed by police in 2014 and asked directly if she knew about his abuse. ""Gavin McKellar asked me if I knew Richard had been abused by a family friend and I said yes, I knew, and I knew who it was.

"Gavin then asked me what I had done about it and I told him I hadn't done anything about it as I didn't know what to do or how to go about it. I was only 18."

Mr Tracey added: "My complaint has never really been with the police but with social services. However, I made these allegations as a child whilst displaying every warning sign in the book and nothing was ever done, this of course includes the many physical assaults.

"When I was eighteen years old I went to the police in Scotland and made allegations about the sexual abuse. The male police officer practically laughed in my face. No investigation ever took place. I'm disgusted and I'll never trust the police again."

A spokesman for Police Scotland said: "We recognise the findings of the Police Investigations and Review Commissioner into how this complaint was handled. We have provided a response in relation to these findings and have implemented the recommendations put forward by the PIRC.

"It would be inappropriate to comment further at this time as other areas of complaint are currently being considered."