in the episode the goodbye look on PLL what did alli bury in the garden that the dog was digging & sniffing at?

In the newest episode of pretty little liars (the goodbye look) when
spencer was bringing the brownies to allisons brother, she was
standing on the porch and turned around and there was a dog trying to
dig something up in the garden, was it something Allison buried? if so
what was it?