A top police chief has slammed "ineptitude" at Police Scotland which "prevented" him from carrying out a full-scale misconduct probe.
Durham Constabulary was called in after Scottish officers were found to have obtained communications data without judicial permission during an inquiry.
But Michael Barton said came up against a "culture of secrecy" in the force.
The chief constable said he wanted "everybody put into a sack and shaken up and told, for heaven's sake fix it".
Police Scotland said a full investigation had eventually been carried out, adding that there had been "significant organisational learning" from the case.
Seven Police Scotland officers from the counter corruption unit (CCU) were cleared of misconduct in January following a lengthy investigation involving several police forces.
Officers were found to have obtained communications data without judicial permission while trying to identify a journalist's sources, after information about the Emma Caldwell murder inquiry was leaked.
But while a watchdog said the failures "could properly be viewed as reckless", senior officers maintained throughout that it had been an issue of "misjudgement" by an officer "misinterpreting" a newly-introduced code.
After the Interception of Communications Commissioner's Office (IOCCO) identified that there had been a breach of protocols in June 2015, Durham Constabulary was asked to look into the breach.
The English force subsequently recommended a full misconduct probe, which was carried out by the Police Service of Northern Ireland - and resulted in all seven officers being cleared.
Mr Barton told MSPs that he had initially been asked to conduct a full investigation, but later found this was downgraded to an inquiry - a lesser form of probe which would mean he would not have access to all documents or be able to interview people under caution.
He said: "As far as I was concerned, I was asked to investigate. That's what I wanted to do. And I was prevented from doing so."
Mr Barton said he was frustrated by the decision, and said there was "a lack of openness in certain parts of the organisation - and that remains so".
He added: "I think currently, the lawyers in Police Scotland are not transparent, and they're overly defensive, and they're risk-averse, and that got in my way."
However, the chief constable said there "isn't any conspiracy in Police Scotland", rather putting the problems down to "ineptitude".
He added: "Individually, there are smashing people in Police Scotland. Everyone we met, smashing people.
"I got dreadfully cross with the legal people and the professional standards department people because I think they misinterpreted the rules, frankly, and I think they're too risk averse, but they're still smashing people. But it's the culture.
"It's that secrecy, that lack of transparency, that's incredibly unfair to everybody, because there isn't speedy justice."
Mr Barton told Holyrood's justice sub-committee on policing that the complaints processes at the Scottish single force needed to be "shaken up".
He said: "What's happened here, over time, is people have dug them into the trenches. So you can't seem to get out of it. I think it's preposterous that in an inquiry I was asked to go and speak to officers, and they couldn't be held to account for what they told me.
"They could have just told me a load of old bunkum and I'd have had to write it down and hand it on to somebody who's investigating, and then they'd look at me and say, 'you're not so good Mick, you've just put a load of bunkum in front of me' because it couldn't be a probing interview under caution.
"I think it's grown over time. But I do think it needs everybody put into a sack and shaken up and told, 'for heaven's sake fix it, and stop it'. Because the only people who are suffering as a result of this are the complainants who are making complaints, and they have a less than optimal service, and the officers themselves, because it's dreadful that they're held under suspicion for quite so long."
Following the conclusion of the misconduct probe, Police Scotland acknowledged that guidelines had been breached and said there had been "significant organisational learning" as a result of the case.
Dep Ch Con Rose Fitzpatrick said: "A full misconduct investigation was carried out by PSNI at our request, which is the element of the process that Chief Constable Barton says he was prevented from undertaking.
"The PSNI investigation found that there was no misconduct on the part of any of the seven officers who were investigated. It is our position, supported by external and independent legal opinion from a QC, that our regulations would not have permitted Chief Constable Barton from carrying out both the complaint enquiry and the misconduct investigation.
"We have previously said that there has been significant organisational learning from these enquiries and a report on this has been provided to the Scottish Parliament's justice sub-committee."
Opposition parties at Holyrood were critical of Police Scotland in the wake of the committee session.
Scottish Conservative MSP Margaret Mitchell, who is also convener of the justice committee, said the evidence given by Mr Barton was "nothing worse than a desperately worrying catalogue of confusion and obfuscation at the heart of Police Scotland".
Labour's justice spokesman Daniel Johnson said the "dysfunctional culture at the top of Police Scotland has been utterly exposed", saying there had been "sheer ineptitude and incompetence" over the inquiry.
Lib Dem MSP Liam McArthur said Police Scotland would have "some extremely serious questions to answer when they appear before the committee next month".