damim, "bloodguiltiness," is that one would be guilty for killing him. If he is found breaking in, and there is fear that when confronted, he may kill the homeowner, then the homeowner is justified in using lethal force. If the sun rises on him, which is explained by Chazal that there is no such fear - if it is clear to you like day that he poses no danger, then the use of lethal force is not justified.
A bill has been proposed in Florida to extend the current law. At present, the homeowner (or car owner) would have to determine for sure that the thief poses a threat. They want to change it so that the default assumption is that the thief poses a threat and can be killed. According to the article:
Under current law, homeowners cannot use deadly force unless they believe an intruder intends to kill them or a loved one, or severely harm them. Although criminal case law tends to favor homeowners, anyone who kills an intruder can be arrested.
Under the bill, anyone who breaks into an occupied house or car would be presumed to have deadly intent. Victims would no longer have to determine the intruder's intent.
"You can't expect a victim to wait and ask, "Excuse me, Mr. Criminal, are you going to rape me and kill me, or are you just going to beat me up and steal my television?' " said Marion Hammer, lobbyist for the National Rifle Association.