This story is creepy, and a bit odd. If
the details about very specific notes and equipment reported in the media are accurate, it does sort of suggest that the two men are 'hired hands' and there might be some Mr Big behind this whose primary intention was, in fact, to knock her off.
You can rob a safe, even a rich persons safe, without having to go to the trouble of murdering, (dismembering?) and disposing of them in body bags unless you really, really want to do them harm more than you want to take their money.
So who in Joss' life or business connections might want that? With the Tupac story rearing its head again, it is worth remembering that there are certain sections of the record industry business where some shady characters wield power and some extremely dodgy goings-on have occurred over the years.
(And I don't just mean Simon Cowell!