Most states have what is typically called a Castle Doctrine that says the application of deadly force is reasonable (thus no civil liability) when protecting your place of dwelling (and occupants) from violent intrusion.

This case would seem to be a perfect example of the doctrines intent.
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I am still not a cop.

EZ Thread Yarn Balls

"I don't care how you catch them, as long as you treat them well and with respect." Lani Waller in "A Steelheader's Way."