离奇案件

..one morning,
my mum found a tuna tin at the back of the house,
placed beside the mop without the label,
and the tin had been slightly opened,
later the label was found near the rubbish bin,
it was so weird that none of us did it.

the tuna tin was belong to my aunt,
she just bought it the day before,
she was not at home on that morning,
so, who did it?

could it be a cat?
impossible !!!
it don't has such big energy to open the tin