US and UK phrenologists encouraged a lot of grave descration, often not even waiting for a corpse to be interned before shipping the remains out.

  Yagan’s murder by colonial settlers was, even by the day’s standards, an act of hideous violence. That his head was subsequently removed and dispatched to England as a biological curio, a specimen to aid the discredited voodoo science of phrenology – whereby racial intelligence and personality could purportedly be determined by cranial distinctions – added indignity to death.

Easy to write off as the bizzarro actions of those gosh darned old timey folks ...

  A naked life size bronze of Aboriginal warrior Yagan, resting a spear across the back of his shoulders. It is quite evident that the head of Yagan is not the original one (rather oversized, has a far too long a neck and is an altogether different shade). I must say that because the statue’s head has been stolen twice (and given the way Yagan died), the sculpture now takes on a strange and ironic overtone. 

but yeah, they just keep stealing that head.