This six-inch black blade belonged to the man on the left. His name is Sir John Williams — the surgeon of Queen Victoria and one of the main suspects in the eleven Whitechapel murders. This may be Jack the Ripper's weapon.
He has been exposed by Tony Williams, his great-great-great-great nephew. Tony found the knife in the possessions left by Sir John, who left London after the murders. Along the knife there were three glass slides containing slices of uterus.
The knife matches the description set by the case pathologist, Thomas Bond. Bond was the Surgeon to the Metropolitan Police's A Division in Westminster. He was also the first criminal profiler in history, precisely after he attempted to describe the personality and modus operandi of Jack the Ripper.
Tony Williams is convinced his distant relative was the murderer and this was his weapon used for the Whitechapel murders. He also thinks that the surgeon motivation was his frustration: his wife couldn't have children and he was trying to find a cure for her infertility. He's going to put it all in a recently released book: Uncle Jack - A Victorian Mystery. For all the people fascinated with this story — myself included — it would be a must read.