A police watchdog has cleared an investigation into the death of a schoolboy at an outdoor activity centre after complaints by his parents.
Thomas Frost, 15, of Penarth, south Wales, was found dead in bed while on a school holiday in Cornwall on July 4, 2003.
The schoolboy, an Ysgol Erw'r Delyn pupil, had been attending Churchtown Farm residential activity centre in Lanlivery, near Bodmin.
Officers with the Devon and Cornwall Constabulary launched an investigation into the death and concluded it was non-suspicious.
Due to a series of forensic tests not being carried out during a later post mortem examination a cause of death was never ascertained.
The boy's father had criticised the way the investigation had been conducted, accusing police of being incompetent and negligent.
He passed on 16 complaints to the Independent Police Complaints Commission (IPCC) against the investigation, all of which were later withdrawn.
The police watchdog regarded them as so serious it decided to go ahead and fully investigate them anyway.
That inquiry has now finished by concluding that the "police investigation was thorough and proportionate."
IPCC Commissioner Rebecca Marsh said: "This was a tragic death for Thomas's family and friends.
"Mr and Mrs Frost have had to endure the death of their child while he was away from their care and support.
"This must be unbearably hard for them and I have every sympathy for them and their grief.
"I have arranged for Thomas's parents to have the IPCC report.
"The investigation we have carried out was extremely thorough and looked at in detail all of Mr Frost's 16 complaints against officers from Devon and Cornwall Constabulary."
She added: "The officers who attended Churchtown Farm residential activity centre after Thomas was found dead in bed acted properly in how they ensured the bedroom where Thomas was found was properly secured, and in their interviews with the centre's staff and Thomas's school, whose responsibility it was to look after Thomas.
"The police conclusion that the death was not suspicious was reasonable."
Because necessary tests were not carried out at post-mortem a subsequent inquest recorded that death was "unascertained".
The post-mortem examination and what forensic tests were carried out were neither part of the IPCC remit nor the responsibility of the police officers, she said.
"The Churchtown Farm activity centre was subject to various examinations by other public agencies following complaints from Mr Frost about them. These complaints also included the pathologist and two coroners.
"The IPCC investigation sought information from all these bodies and individuals to better understand their conclusions about what had happened at the centre and who had responsibility for different aspects of Thomas's care.
"Our investigation report summarises all of this information and sets out the arrangements Thomas's school, Ysgol Erw'r Delyn, Penarth, Cardiff, had entered into with the centre and what its responsibilities were as well.
"The subsequent police investigation followed force policy and procedures and considered the possibility of foul play. It reasonably decided that this was not a suspicious death.
"Because of the absence of some forensic tests it was not possible for forensic experts, including eminent pathologists, to determine what the exact cause of death was."
The full investigation report is available on the IPCC website - http://www.ipcc.gov.uk/frostËfinal.pdf