There was a note of resignation in the statement yesterday by Lenny Harper, the deputy chief officer of States of Jersey Police, that there may never be enough evidence to mount a murder inquiry into the partial remains of five children found at Haut de la Garenne.

As a policeman who has been central to the painstaking efforts to sift and analyse bone fragments and teeth found in the cellars of the former children's home, Mr Harper is clearly eager to bring to justice anyone responsible for whatever crimes took place. As an employee of a government whose commitment to this investigation has been at best lukewarm, however, he knows that the case appears, for the moment, to have reached a dead end. His job, and that of the Jersey government, is to ensure that this case remains open and that the inquiry goes on.

To the public, things appear straightforward. Dozens of Jersey residents have testified that, as children sent to Haut de la Garenne, they suffered physical and sexual abuse and knew about punishment rooms in the cellars. A police investigation, the biggest mounted in the Channel Islands, has uncovered underground rooms and found disturbing evidence: a shallow concrete bath with blood on it and the words “I've been bad for years and years” scrawled on a wooden beam, the letter K written in black on a wall with whitewash covering the rest of the word, a total of 65 milk teeth and more than 100 human bone fragments, one coming from a child's leg and another from a child's ear.

In addition, a member of the public said that he had been told by staff to dig two holes near the boys' dormitory, and police have found in one of them a large amount of lime at the bottom. That is certainly enough to prompt the reasonable suspicion that horrific crimes, including murder, have been committed at the home.

Bringing specific charges may prove to be much more difficult, however. First, the timeframe being investigated ranges from the late 1940s to the 1980s, and the remains, which were burnt, cannot be carbon-dated. Secondly, there are no reliable reports of missing children during this time, as those sent to the home were often illegitimate, unwanted or were listed as simply having left for the mainland. And thirdly, although some 97 allegations have been made of abuse dating back to the 1960s, and more than 100 people listed as suspects, several potentially key witnesses are dead and there are no clear links between the abuse and murder.

The frustrations of the case have also been reflected in public attitudes. Many people in Jersey, especially at the start of the investigation, have been angered by what they see as attempts in Britain to disparage their system of justice, force the pace of the investigations and impose independent judicial control. A former health minister, a trenchant critic of the Jersey government's attitude, was sacked and Mr Harper himself is known to have been close to resignation over official reaction to the abuse inquiries.

The Jersey government should take a more robust stance over what has happened. For Britain, this is a delicate matter. The island, a Crown dependency, is not part of the United Kingdom and not subject to Home Office regulation. Ministry of Justice officials have held talks with those involved in the case and although there are ways of intervening - either directly or through the Privy Council - the British Government is extremely loath to do so or pre-empt the findings of an investigation still under way. But it should not be necessary. However baffling the case, it remains a homicide investigation. There is no reason to curtail or curb it. What happened in the dark cellars of Haut de la Garenne must be revealed, whatever the financial or political cost.