Missing boy's brother claims he was threatened by police Kevin Allen's 15-year-old brother Martin disappeared in November 1979 Mr Allen claims when he said he suspected a top level cover-up over the disappearance he was told "stop talking like that, you might get hurt Now believes files have been destroyed or lost to avoid solving the mystery Martin's disappearance has been linked to the notorious Elm Guest House The brother of a missing teenager claimed he was threatened by police when he told them he believed they had covered-up his disappearance.Kevin Allen's 15-year-old brother Martin disappeared in November 1979. The son of the chauffeur to the Australian High Commissioner, Martin vanished on his way home from King's Cross Station to his home in Kensington. Martin Allen (pictured) was abducted thirty years ago in London and has not been seen since. He disappeared on his way home from school on Guy Fawkes Night in 1979 - his brother claims he was threatened by police But the Sunday People reported that when Mr Allen pushed for more to be done on the case, saying he believed a top level cover-up was hiding the circumstance of the teenager's disappearance, he was told to "stop talking like that, you might get hurt." Mr Allen, 51, now believes the files relating to Martin have been destroyed or lost to avoid solving the mystery that has haunted his family for 35 years. Speaking to the Sunday People yesterday, he said: "I've no faith in the police. They failed us. "Within a couple of months of Martin disappearing, my father said: "There's something not right here." 'Police weren't doing enough. They went through the motions. So it didn't surprise me when a senior officer warned me I could get hurt. Mr Allen said he always believed there was "Establishment involvement" in his brother's disappearance. Martin's disappearance has been linked to the notorious Elm Guest House in Barnes, south west London, and the alleged VIP paedophile brothel is now being re-investigated. Martin's disappearance has been linked to the notorious Elm Guest House in Barnes, south west London, (pictured) and the alleged VIP paedophile brothel is now being re-investigated Police fear the youngster may have been snatched by a man while on the Tube home. Last week, the father of eight-year-old Vishal Mehrota also told newspapers that he believed his son's disappearance was a result of a murky underworld of high-level sex abusers. Vishal was also walking home when he disappeared in 1981, parts of his dismembered body were recovered months later in woodland. An open verdict was recorded by a coroner who said "foul play" was likely.