When someone disputes this, a "respected astronomer" (who just so happens to be the coroner's best friend) states that the evidence points strongly toward an "extremely localized meteor shower". The coroner agrees with this, citing the fact that he knows all about these sorts of things, even going so far as to call himself a "meteor-ologist"
Downplayed: Alice is found dead with a knife in her chest such that it is possible that her death could have been an accident. A few characters actually believe it.
The local government wished to make an example of Alice in a way they could plausibly deny to neighboring states.
Alice was such an awful person, no one feels sorry for her.