Not self-defense, but if that's the only way to stop a robber, I think the law should permit it. Property is a very fundamental right. Seems that in a case like this where a robber, who used credible deadly force threats to accomplish a larceny, and is killed at some point after the robbery, but while still in "the heat" of the felonious act, and when no other action will stop the robber from absconding with the ill gotten goods, an exception ought to be codified in law.