A confidential report has indicated there were grave concerns for the safety and well-being of Daniel McAnaspie, who went missing from State care and was found stabbed to death earlier this month.
The Health Service Executive report also said the 17-year-old had been moved around more than 14 times between residential care, out-of-hours services and family members during the last nine months of his life.
Four men arrested today in connection with the killing of the teenager are still being questioned.
The report, seen by RTÉ News, says that he was becoming immersed in what it called 'a dark world of drug abuse and criminality'.
The HSE knew Daniel McAnaspie was using drugs - smoking cannabis and taking benzodiazepines - sleeping pills and valium, which led to his behaviour becoming 'increasingly erratic'.
It also shows that Daniel was denied Secure Care in May of last year and that even though the decision was appealed his case was closed by the Special Care Committee.
The report does show however that he responded well when he did get help - he tested negative for benzodiazepines after attending a drug abuse service specifically for young people.
The report states that Daniel had 'a horrific upbringing fuelled with parental death, drug and alcohol abuse and significant neglect.'
The Health Service Executive has said it will be seeking to fully co-operate with the independent group set up to review the deaths of children in care.
In a statement this evening, the HSE said the handover of files to the review group needed to be conducted in a way that protected the rights of the children involved.
The Executive said it was seeking legal guidance on how best to do this.
Arrests
Four men have been arrested in connection with the murder of the Dublin teenager.
The 17-year-old went missing from HSE care and was found stabbed to death earlier this month.
The four, who are all in their 20s and 30s and from the Blanchardstown area, are being questioned at various garda stations in Dublin.
Two are being held on suspicion of murder, the other two on suspicion of withholding information.
Detectives investigating the murder have for some time had good information on what happened to the teenager.
Daniel was last seen in Whitestown Avenue, west Dublin, in February. He was in a house there before he was killed.
His body was found on 13 May on land in Rathfeigh, Co Meath, off the N2 Dublin to Derry road.
A post-mortem examination revealed that he had been stabbed at least six times in the upper body and throat.
The two being detained under Section 30 of the Offences Against the State Act in Finglas and Blanchardstown garda stations are being held on suspicion of witholding information.
The other two at Cabra and Finglas are being held under Section 4 of the Criminal Justice Act on suspicion of murder.
The HSE will also be investigating Daniel's case but investigators have not yet been appointed, the investigation has not begun and the HSE does not know when it will.
