DNA has almost certainly identified the killer. In 2007, Russell Edwards bought a bloodied auctioned shawl taken from one of the Ripper's victims and had it scanned for DNA. The shawl was more expensive than Catherine Eddowes probably could have afforded and raised the possibility that the killer had handled it.
The unfortunate Ms Eddowes left 126 year old traces but so did Aaron Kosminski, the chief original suspect. The researchers went to descendents of Eddowes and Kosminski and found a perfect match for both. The little lights came on with the Kosminski genes, blinking at the 95% confidence level. This could collapse an entire publishing industry.
The story broke first at The Daily Mail.