It is one of the world's greatest murder mysteries which has baffled investigators for more than a century. But now an author and self confessed "armchair detective" claims to have solved perhaps the most notorious whodunit ever, and discovered who Jack the Ripper was. Russell Edwards claims Aaron Kosminski, a 23 year-old Polish immigrant who ended up dying in an asylum, was "definitely, categorically and absolutely" the man behind the grisly killing spree in 1888 in London's East End. Mr Edwards said a blood-stained shawl he bought in 2007 after an auction in Bury St Edmunds, Suffolk, held vital DNA evidence which led him to the killer. He said: "I've got the only piece of forensic evidence in the whole history of the case. I've spent 14 years working on it, and we have definitively solved the mystery of who Jack the Ripper was. "Only non-believers that want to perpetuate the myth will doubt. This is it now - we have unmasked him." Jack the Ripper murdered at least five women, slashing their throats, removing some of their internal organs and leaving their mutilated bodied in Whitechapel's darkened alleyways. Mr Edwards, 48, from Barnet, north London, was "captivated" by the murder mystery and had been investigating it in his spare time, but had come to the conclusion it could never be solved. But then in 2007 he saw a shawl found by the body of Catherine Eddowes, one of the Ripper's victims, was up for sale. He bought it, and enlisted the help of Jari Louhelainen, an expert in molecular biology, who used pioneering techniques to find DNA from her blood and that of the killer. More via Yahoo News UK.