Hellenistic Era Grave at Amphipolis.

[Lysandros]

I completely missed this... though I sometimes have a look into To Vima. I hope it is ok if I post a link with a video and some pictures: http://www.tovima.gr/culture/article...BF%CE%BB%CE%B7
So far the grave is dated to 325-300 BC (which again rules Seleukos out ;)).
It seems Roxane and Alexandros IV were first kept prisoners in Amphipolis and then murdered there in 310 BC. Of course, one can only make a guess at this point, but if it really is a royal tomb (and it surely looks like it could be) it would fit well not to bury Alexandros IV and Roxane in Aigai/Vergina where the old Macedonian kings were buried but in Amphipolis instead, especially if one (Kassandros, that is) claims the power for himself (and the other Diadochi had no interest in keeping them alive, too). So after killing them it would be - from Kassandros' and other Diadochi's point of view - perhaps suitable to honour their former position by the construction of such a tomb (and thus preventing their bodies being brought elsewhere...).
As for Kassandros, he died in 297 BC probably of a sickness, but I couldn't find anything in the sources directing to his dying or resting place.