What's this group about, and how was he killed?
Killed in an accident.
They believe in reducing taxes and coercion. One of their strong desires is to limit the power of the federal government in the states by refusing federal mandates enforced by monetary extortion. These exist in many forms, but essentially say "Do what we say, or we will not give back the money we took from you."
It is generally known as "revenue sharing". It is how the federal government has enforced ever more intrusive control over schools, peace officers, collection of citizen data bases, and land use.