The  Interesing thing about the two letters from the Police Historical Unit is that two men with the surname McNamara are appointed on the same day in 1853.

This is where

the author of the story made the decision that Frank The Poet changed his name to avoid any confusion.

But it also suggests that there is more to this story.  

Here we see the partial police records of three detectives involved in the escort robbery investigation. Top left is one of seven pages of 'defaults' recorded against Detective Hudson. Bottom Left is the default sheet of Detective Tuckwell and bottom right is Detective Thompson's record.  It is tempting to judge these men's records as quite alarming as some of the charges against them appear serious to us. It is clear that they were often very drunk but the police were strugling for numbers in a pretty wild town so they may not be as bad as we might first think.