I think that would have made him angry enough to go after something belonging to Gryffindor, just to make sure he had a tie to Hogwarts yet again. Or, in a rather devious move, he'd turn one of the library books into a Horcrux. Maybe it would be a book that he enjoyed reading in the library; he'd definitely let it stay there, however I think he would have placed strong wards on it so that no-one besides him would be able to find it. Now that would have thrown the Trio for a loop.

Lena/Gryffindor/2