Here is something I just found
Kellermann-Gun Ownership as a Risk Factor for Homicide in the Home
A subsequent study, again by Kellermann, of fatal and non-fatal gunshot woundings, showed that only 14.2% of the shootings involving a gun whose origins were known, involved a gun kept in the home where the shooting occurred. (Kellermann, et. al. 1998. "Injuries and deaths due to firearms in the home." Journal of Trauma 45:263-267) ("The authors reported that among those 438 assaultive gunshot woundings, 49 involved a gun 'kept in the home where the shooting occurred,' 295 involved a gun brought to the scene from elsewhere, and another 94 involved a gun whose origins were not noted by the police [p. 252].") (Kleck, Gary. "Can Owning a Gun Really Triple the Owner's Chances of Being Murdered?" Homicide Studies 5 [2001].)
Additional analysis of Kellermann's ICPSR dataset shows t
hat just over 4½ percent of all homicides, in the three counties Kellermann chose to study, involved victims being killed with a gun kept in their own home (see derivation). This supports the conclusion that people murdered with a gun kept in their own home are a small minority of all homicides
even DU bashes Kellerman's nonsense
"A gun in the home is 22 times more likely to kill a family member than an intruder" - Democratic Underground