A 59-year-old convicted sex offender currently imprisoned in Colorado is once again the focus of the investigation into the 1996 murder of child beauty queen JonBenét Ramsey in Boulder. Handwriting analysis by two experts has linked letters written from prison by Gary Oliva to the infamous ransom note written by Ramsey’s killer. Handwriting experts Mozelle Martin and Dawn McCarty, who had been hired by private investigator Jason Jensen, both told The U.S. Sun that they had found “several significant similarities” between the handwriting of the ransom note and that of Oliva in his letters. Jens…