Once Alysia left, Sirius returned to the woods, deciding it would be best not to be seen by anymore students. He was careful to remain in roughly the same area, not straying too far, and never going too deep into the woods. He knew all too well what lay in there.
The next night, Sirius was waiting, hidden in the undergrowth as Alysia arrived. He didn't emerge immediately, instead he waited, making sure she was completely alone, before he emerged, approaching her with a wagging tail, moving towards the bag of food and sticking his nose in, taking a long smell of it, then pulled a piece of food out of the bag, digging in immediately.