What are the most recent three year (or more; five years is better) complete
data for firearm (pistol and rifle) homicides in the US? Specifically, how
many persons are killed annually by police action, criminal activity, self
defense by civilians, accident and suicide, or other causes? My intent is to
learn how many were innocent victims, such as law abiding persons caught in
a drive-by shooting. In a gang shootout, to me, the victims are not innocent, if
they were exchanging fire. I realize of course that subtle distinctions may not
appear in published data. 
Thanks, monroe22-ga

What an intriguing question! Unfortunately, I haven't found an answer.
But here's something that is important, if true:

"A criminal homicide involving a firearm occurs in the United States
about once every half hour -- but two-thirds of the fatalities are not
completely innocent victims but themselves have criminal records.

Source: FBI Uniform Crime Reports and Murder Analysis by the Chicago
Police Department"

http://www.usa2076.com/proguns/gunclock.htm

Of course, the fact that a person has a criminal record does not
necessarily mean that the person was engaged in criminal activity at
the time of the shooting. But it's interesting information, if it is
accurate.

People tend to think of gunshot victims as bystanders to whom an
unforeseeable tragedy occurs: sweet little granny ladies or angelic
children who were in the wrong place at the wrong time. My friends in
law enforcement have told me that this stereotype is seldom accurate.

pinkfreud-ga: Dear Pink: Your always interesting input is greatly appreciated.
The data referenced (if accurate, as you cautioned) is a helpful
beginning in trying to get a rounded view of this issue. My own
attempts at researching it were frustrating...too much conflicting and
confusing data. I leave it in the capable hands of the GA Researchers.
Thanks, monroe22