A father who felt his son's death was not properly investigated feels cheated two police officers retired before being disciplined, says a watchdog.
Robbie Powell's father has made a series of complaints to the IPCC
The Independent Police Complaints Commission (IPCC) said Will Powell's feelings were understandable.
It said Dyfed-Powys Police should apologise, but cleared former chief constable Terry Grange of misconduct over the officers' departure.
Robbie Powell, 10, died in 1990 of natural causes aggravated by neglect.
A Swansea inquest in 2004 heard evidence that a succession of doctors who saw Robbie in the weeks before he died had not recognised the symptoms.
His symptoms of sickness and stomach pain were thought to be gastroenteritis, but he died from Addison's disease.
Dyfed-Powys Police conducted a series of investigations into the death, but Mr Powell claimed these were mishandled.
An investigation into the force's handling of the matter was conducted by Avon and Somerset Police, which found it was badly managed by senior detectives.
Mr Powell complained that Mr Grange allowed two of them to retire before they were due to face disciplinary action, and before police had secured statements from them.
The IPCC investigation has concluded it was "unlikely" anything could have been done to stop them leaving, as they were not subject to suspension at the time.
It said: "It is entirely understandable that he (Mr Powell) feels cheated over the retirement... and the fact they were not held accountable for their inadequate management of the investigation.
"However, that does not alter the fact that ultimately there is no evidence of misconduct in the chief constable's actions and decisions in respect of these officers."
The IPCC suggested in future the force recorded the decisions and rationale concerning the suspension (or not) of police officers or staff and these were highlighted to all relevant individuals.
Dianne and William Powell fought for 14 years for an inquest
IPCC commissioner for Wales Tom Davies said: "We appreciate that this is a difficult time of year for Robert Powell's family and again I would like to pass on my condolences to them.
"The effect of the inadequate and ineffective police investigation for the Powell family cannot be underestimated and we have recommended to Dyfed-Powys Police that the chief constable makes a public apology to them."
Mr Grange himself has since retired amid a separate inquiry by the IPCC into allegations of potentially criminal financial irregularities.
However, his retirement meant the IPCC had to drop inquires into further allegations that he had misused police computers, because they were not potentially criminal.
The IPCC's call for an apology from the chief constable, however, refers not to Mr Grange, but his replacement.
The police authority has defended its decision to allow Mr Grange to retire, saying it was not appropriate to suspend him and that it acted to maintain public confidence in the force.