Mather's ancestors were from England, and he was proud of that fact. It was very common to see him dressed in royal blue and red, even after he aged. Some of the immediate members of his family were lawmen in Massachusetts, and Mather acquired the desire to become a lawman himself.
Mather was also seen visiting Denver quite a number of times. He frequented casinos there but he usually avoided getting involved in gambling activites.
There is a legend that Mather killed seven men from the Henry bunch gang after they had shot marshall Tom Carson to death. According to the legend, Mather promised Carson he would get each of the gang's gunslingers and shoot them down. Mather went after the gang members, and shot them each on the street, killing all seven gang members.
Mather wouldnt talk about the incident, but a few weeks later, a preacher came into town and was holding services, when one night, Mather walked into the religious event, after having been drinking alcohol. The pastor commented that he would gladly die to save the man who had sent seven men to hell and Mather dissaproved of his comment, so he shot the pastor to death.
Mather later tried to open a saloon, however, he was met with the dissapproval of marshall T.C. Nixon. Nixon and Mather had a street-fight in which Mather came out with a shoulder injury. Immediately after, Mather threatened Nixon, telling him to leave town for his own good. However, that same niht, they met again, and Mather shot the marshal to death.
After this incident, Mather preferred to leave town. He went by horse to San Francisco, where he took a ship to Vancouver. In Vancouver, he served with the Royal Canadian Mounted Police until the latter years of his life.