Collin Murphy married Marion, and they had several children: their oldest, Karrin, at least two sons, and their youngest, Lisa. He worked as a Black Cat in the Thirteenth Princinct in what later became Chicago Police Department#Special Investigations
He killed himself when Karrin was 11. The work got to him, he grew distant and started to drink a lot. Karrin never knew of his prior work, her mother never having told her. "Jack" Murphy nicknamed his daughter "Karrie" and is grateful that Dresden looked after her.
He worked with Henry Rawlins when Karrin was a little girl and Rawlins is the only other person who could call her "Karrie". He was responsible for saving Rawlins from a non specified supernatural threat thirty years previously.
His full title and name is Captain Collin J. Murphy, and in Ghost Story he is also known as "Jack". By this time, he works as the head cop in the Between, and drives Dresden in an old Skylark. Uriel said that Collin, like the others who work for him in his Between Office, is there because he's not ready to "what comes next". When ready, he'll take the next step.
Collin, "Jack", had the look of a boxer with scars here and there around his eyes and nose. His huge forearms were about as strong as telephone poles. He had blond hair, blue eyes, and a heavy jawline.
In the seriesEdit
In Dead Beat, the ectomancer Mortimer Lindquist knows his ghost and finally agrees to help Dresden find information from the spirits on the necromancers, the Heirs of Kemmler because Lindquist knows him and for Karrin Murphy, his daughter.
Dresden hears the story from Henry Rawlins about how thirty hears ago, when Henry was a young cop, he went down an alley after hearing a woman scream. He saw somethng that still gives him bad dreams. It was strangling the girl, Henry emptied his gun into it, but it picks him up and slams him into a wall. That was when Collin Murphy showed up with rock salt loaded in his shotgun and killed it. The sun rises, burning it.
In Ghost Story, Harry Dresden is brought to his office in the Between by Ron Carmichael's ghost. "Jack" informed Dresden that there's an irregularity with his death, that the "opposition" wanted Dresden out of the way and broke the law—they cheated. Jack assigns Dresden the task of solving his own murder in order to save three people he cares about who are in danger if he doesn't. He's not told which three. It's risky because Dresden could be trapped there as a spirit for eternity if he never finds to killer. Dresden discovers that Jack is really Captain Collin J. Murphy, Karrin Murphy's dad who used to run the Black Cat Investigations Department of the CPD.
Jack drops Dresden off at Mortimer's house. When Dresden asks, he said he has no messages for Karrin, he's done her enough damage. He also said that telling Lindquist that he sent Dresden might be a help. Dresden tells Sir Stuart Winchester that Jack Murphy sent him. Sir Stuart said: "A good fellow. For an Irishman".