The murder of 12-year-old Keith Lyon shocked the nation. The 12-year-old boy was stabbed to death on the Sussex Downs in 1967 on his way to buy a geometry set with his pocket money. Despite one of the biggest investigations ever launched, no one was charged with the killing.

Now, more than half a century later, his younger brother, Peter Lyon, hopes that fresh evidence could finally establish what happened on that afternoon of 6 May 1967 in the same way that Sussex police were last year able to solve the “Babes in the Wood” case, also in the Brighton area, 32 years after those murders.

“The older I get, the more desperate I am to have it finally solved,” 59-year-old Lyon told the Observer.

Keith, son of well-known Brighton band leader Ken Lyon, was walking from the family home in Ovingdean to nearby Woodingdean when he was attacked and stabbed to death. The insides of his pockets were pulled out and the four shillings he had with him were missing. His father was playing at a ball in Brighton when the police informed him of the murder.

Detectives believed Keith was attacked and robbed by three boys. There was a report of a fracas near the scene where Keith’s body was later found by a woman walking her dog on the bridle path from Roedean school to Woodingdean. A white-handled steak knife was later found, and a bus driver reported seeing two youths in an “agitated state” on his bus to nearby Whitehawk.

Some 2,000 children were interviewed, 6,000 fingerprints taken and 75,000 house-to-house calls made. But no one was charged. The case was reopened in 1976, 2002 and again in 2006 – still to no avail.

Then, earlier this month, police were told that a local man, who had become an alcoholic, had confessed his involvement in the killing to his mother, who had told a health worker in confidence. The man has now died. “Perhaps he had become an alcoholic because he could not deal with what he had done,” said the person who passed this information on to Sussex police. The hope now is that, if the man’s involvement is confirmed, his schoolboy associates might also be identified.

Facebook Twitter Pinterest An undated photograph of Keith Lyon. His brother, who was seven when Keith was murdered, said: ‘I often think of what Keith would have become. He was a very talented musician.’ Photograph: Peter J Jordan/PA

Lyon said: “I still have hopes, after all this time, that the people responsible will be identified. The ‘Babes in the Wood’ case showed that it is still possible.” Like his late father, Peter Lyon is himself a musician, and played with the bands Love Affair and the Vandells. He now teaches music in Thailand and has recorded a song, Bird of Pain, about his brother. He was seven at the time of his brother’s murder, and his main memory of the time is of entering rooms in the family house and finding his parents weeping. Ken Lyon died in 1991 and the boys’ mother, Valda, in 2005.

“It has had an enormous effect on my life,” said Lyon. “Having a son myself makes me realise what my parents went through, and I often think of what Keith would have become. He was a very talented musician – he played the piano and the clarinet. He would have been in his 60s now and I am sure he would still be playing.’’

Lyon hopes that the consciences of those involved in the death, perhaps one who did not carry out the actual stabbing, might finally prick them enough to come forward.

Sussex police, who have kept the file on the murder open in what is now called Operation Engine, would dearly love to solve it in the way that they concluded the Babes in the Wood case decades after it had taken place: Russell Bishop, aged 52, was finally convicted in December last year of the 1986 murders of Brighton schoolgirls Nicola Fellows and Karen Hadaway.

A police spokesman said that the new information was “currently being assessed to see whether [it] would lead to new lines of enquiry”. Some DNA was identified, believed to have come from up to three people, when the case was further examined in 2006. Some of it may have come from one or more of the suspects.

A Freedom of Information request for the file on the case indicated that, in 1969, a 22-year-old man was arrested but there was “insufficient evidence to prosecute”.

A request for greater detail was turned down.“The release of what might appear to be even the most innocuous information could be of critical importance to an experienced investigator,” said the quality manager at the National Archives, who added that releasing details of the case would “likely be highly distressing for the victim’s surviving immediate family”.

“I am the last member of the family and I am already ‘highly distressed’,” said Lyon. “But I feel I have to kick up the leaves and keep the case alive.”