Police on Jersey say they are unlikely to launch a murder investigation, despite the discovery of partial remains of at least five children at a former care home, because the bones cannot be dated.
The news emerged as a group of MPs was due to meet a government representative today about the rule of law on the island, amid allegations of an attempted cover-up.
So far, 65 milk teeth belonging to children aged between four and 11 and more than 100 bone fragments have been found at the former Haut de la Garenne home.
But forensic scientists are unable to put an exact date on them, said Deputy Chief Officer Lenny Harper, who is leading the investigation.
"We were pinning our hopes very much on the process of carbon-dating," he told BBC radio. "The latest information we're getting is that for the period we're looking at, it's not going to be possible to give us an exact time of death.
"The small number of bones that we've had carbon-dated up until now have given us different readings. One bone, we were told there was a probability that the person had died in 1650 but also a smaller probability that they died in 1960."
He added: "At the end of the day there just might not be the evidence there to mount a homicide inquiry to bring anybody to justice for whatever crimes took place."
But he said a "number of valuable pieces of evidence" had been unearthed which substantially corroborate accounts of abuse at the home given by victims and witnesses, including DNA samples and shackles.
About 100 people have made allegations of abuse going back as far as the 1950s.
Police said the teeth were in a condition which meant they could only have come out after death, while the bone fragments identified so far included one from a child's leg and another from inside a child's ear.
There was evidence that they had been burned and that attempts had been made to move and conceal them in the late 1960s or early 1970s.
Liberal Democrat MP John Hemming, who has previously signed a House Commons motion calling for transparency in Jersey affairs, will be discussing the rule of law in Jersey with a government minister on Thursday.
"There are five cases where there is sufficient evidence to prosecute but the prosecution has been shut down in some form or other," he told BBC radio.
"There are efforts to cover this up - I don't think there is any doubt about that."
So far three people have been charged with sexual offences against young boys and girls as part of the inquiry.