From a DOJ study that looked at shootings for the yrs 2000 - 2004 for the FBI, DEA, ATF, and US Marshals:
267 shootings:
105 during "enforcement operations"
60 intentional discharges at animals
14 unintentional discharges during enforcement ops
88 unintentional discharges during non enforcement activities
One third/33% of their total shootings were unintentional!?
About one in eight during ops were unintentional!?
Nobody can be too careful?
