Sean McGann murder: 'Helpful' calls over 1979 child murder
Police investigating the murder of a 15-year-old boy as he was on his way to a funfair 40 years ago have received "helpful calls" since a re-appeal.
Sean McGann was found dead in an alleyway at the back of Birchfield Road East in Northampton in April 1979.
Police earlier this year revealed they had made inquiries into nearby graffiti and a letter to Sean's family, claiming the author had "important information".
Det Ch Insp Joe Banfield asked people to "search their consciences".
On Tuesday 17 April 1979, between 17:30 and 18:00 BST, Sean left his grandparents' home in Victoria Gardens in Northampton to visit a funfair at Midsummer Meadow.
He failed to return home and his body was found by a passer-by at 08:10 the following day.
Sean had been strangled and police think his killing may have been sexually motivated.
No-one has been charged over his death but Sean's family received a letter from an anonymous writer in 1991.
Det Ch Insp Banfield said on the 40th anniversary of Sean's murder that he believed the writer "had some really relevant information... about the crime".
On the BBC's Crimewatch in September this year crime scene photos which identified chalk graffiti were revealed to the wider public for the first time.
The graffiti said "very sorry" and "No I'm not".
Det Ch Insp Banfield said that following their re-appeals police were working through "some helpful calls and pieces of information from members of the public".
"I would like to take this opportunity however, to appeal again for people to come forward if they know anything they think could be helpful to our investigation.
"I am convinced someone out there knows something and I would ask them to search their consciences for the sake of Sean's family and tell us what they know."