A new inquiry into a historic paedophile ring in North Wales care homes has uncovered "significant" fresh evidence of "systematic and serious sexual and physical abuse".
Detectives from Operation Pallial, which launched last November, have received 140 allegations relating to 18 care homes between 1963 and 1992, including fresh claims by 76 new complainants.
The alleged victims were aged between seven and 19.
Today's report said a total of 84 people - 75 male and nine female - were named by complainants.
Of these, 16 were named by more than one alleged victim and 10 may now be dead.
The large number of alleged victims and care homes, and the duration of the period involved, is much wider than previously thought.
Detective Superintendent Ian Mulcahey, the senior investigating officer, said: "These are serious allegations that will be thoroughly investigated.
"Many have provided graphic accounts of abuse, in some cases of very serious criminality."
He added: "We are prioritising our work focusing on those individuals who pose the greatest risk to the public.
"I want to reassure the community we are taking their allegations seriously."
The publication of today's report on phase one of the inquiry comes less than a week after a man was arrested in Ipswich, Suffolk, accused of "a number of serious sexual offences against a number of individuals", the Serious Organised Crime Agency (Soca) said.
He was arrested last Tuesday and taken to a police station in North Wales where he was interviewed over recent allegations of historic abuse and then bailed to the end of July, pending further inquiries. Soca refused to give his age.
He is the first person to be detained so far as part of the inquiry.
North Wales Chief Constable Mark Polin, who asked the National Crime Agency (NCA) to run Operation Pallial, warned offenders: "If you believe that the passage of time will reduce the resolve of Operation Pallial or any police force to identify people still alive who have caused harm to others and bring them to justice, you are are sorely mistaken.
"People who commit serious and sexual offences should live with the knowledge that we will always examine new information and evidence and seek to bring them to justice for their crimes.
"Offenders should quite rightly have to look over their shoulders for the rest of their lives."
The NCA was selected at the request of North Wales Police to ensure the inquiry's independence.
It was set up to re-examine claims of sex crimes and look again at the original police investigations into abuse at care homes in North Wales.
Mr Polin said: "I took the decision to ask the NCA to investigate these allegations, conscious that some victims of historic abuse may not have the necessary level of confidence in North Wales Police to report matters directly to us.
"Pallial has now secured accounts from almost all victims who are willing to support an investigation and it makes absolute sense for the officers and staff involved to be at the core of phase two and to move matters forward as quickly as possible."
He added it was "never too late" to report abuse and urged anyone who has not come forward yet, to do so.
The investigation is being carried out by 31 officers drawn from Soca, the Child Exploitation and Online Protection Centre (Ceop) and police forces from across England.
Detectives are hoping to develop forensic leads through scientific advancements which might not have been previously available.
In 2000 the Waterhouse Inquiry was established to study claims linked to homes in the former council areas of Gwynedd and Clwyd since 1974.
Following Waterhouse, eight people were prosecuted and seven were convicted.
Around 140 compensation claims were settled on behalf of the victims.
But victims have since said that the inquiry examined only a fraction of the abuse which took place.
High Court judge Mrs Justice Macur is leading a review, which will look at whether specific allegations were not investigated, and urged alleged victims and all other interested parties to give further evidence.
Today's report found no evidence of police misconduct in connection with the earlier investigation.
Peter Watt, director of the NSPCC helpline, applauded today's update.
He said: "This investigation is a major step forward into probing claims of widespread child abuse.
"Many who have been waiting decades for justice and for their voices to be heard have now finally found the courage to come forward and we mustn't fail them this time.
"The NSPCC is providing a round-the-clock helpline - 0800 389 6176 - which has already taken 124 calls relating to this inquiry.
"We would urge anyone who has any information about abuse to contact us or the police immediately.
"While the current focus is, quite rightly, on helping those who were abused some years ago we also have to remember that child abuse is still very much an issue today and many children across the UK are at risk right now.
"This is potentially another sad chapter of child abuse following the devastating revelations of the Savile investigation and shows we all have to remain vigilant to protect vulnerable children."