There have been numerous unsuccessful attempts in the seventy years since its discovery to crack the letters found at the rear of the book, including efforts by military and naval intelligence, mathematicians, and amateur code crackers. In 2004, retired detective Gerry Feltus suggested in a "Sunday Mail" article that the final line "ITTMTSAMSTGAB" could stand for the initials of "It's Time To Move To South Australia Moseley Street..." (Jessica Thomson lived in Moseley Street which is the main road through Glenelg). A 2014 analysis by computational linguist John Rehling strongly supports the theory that the letters consist of the initials of some English text, but finds no match for these in a large survey of literature, and concludes that the letters were likely written as a form of shorthand, not as a code, and that the original text can likely never be determined.