In Colorado our statutes allows for killing of someone attempting to commit First Degree Arson. I bet Michigan has a similar statute.
“18-1-705 Use Of Physical Force In Defense Of Premises
A person in possession or control of any building, realty, or other premises, or a
person who is licensed or
privileged to be thereon, is justified in using reasonable and appropriate physical
force upon another person
when and to the extent that it is reasonably necessary to prevent or terminate what
he reasonably believes to
be the commission or attempted commission of an unlawful trespass by the other
person in or upon the
building, realty, or premises. However, he may use deadly force only in defense of
himself or another as
described in section 18-1-704, or when he reasonably believes it necessary to
prevent what he reasonably
believes to be an attempt by the trespasser to commit first-degree arson.”
I’m not sure about defending property but Michigan gives pretty free reign to use lethal force to defend people.
In this case I think a decent judge would consider the arson a threat to life.