Letter appeal in Sean McGann 1979 Northampton murder case

No-one has ever been charged over the death of Sean McGann in April 1979

A person who wrote a letter to the family of a murdered 15-year-old boy claiming they had "important information" about his killer is being sought by police 40 years on.

Sean McGann was found dead in an alleyway at the back of Birchfield Road East in Northampton in 1979.

Police hope someone may recognise the handwriting of the letter, which the family received 12 years later.

They will also carry out a forensic review of the original evidence.

In a statement issued by police, Sean's family said he was a "much-loved son, brother, grandson and nephew and is greatly missed".

"He was a gentle, loving boy only just past his 15th birthday. He enjoyed spending time with his family, loved horses and horse riding," the family said.

"Forty years on we still think of him every day."

During the original investigation, police handed out leaflets at a Northampton Town match

A boy of similar build to Sean McGann walked around the County Ground in the 1979 investigation

Police set up a mobile station near the murder site in Northampton

On Tuesday, 17 April 1979, between 17:30 and 18:00, Sean left his grandparents' home in Victoria Gardens, Northampton, to visit the funfair at Midsummer Meadow.

He failed to return home that evening and his body was found by a passer-by at 08:10 the following day. He had been strangled.

Det Ch Insp Ally White, of Northamptonshire Police, said: "We don't know for sure whether or not he got to the fair. We believe he was killed elsewhere and taken to this location sometime between 06:45 BST and 08:10 BST.

Police said the letter to Sean McGann's family had only recently come to light

"His jacket and glasses were missing and have never been found, and his shoes and belt had been left a short distance from his body.

"It's very possible that someone knows who murdered Sean, or has information they didn't share at the time which may provide that all-important missing piece of the jigsaw."