they must have left rather a lot of fingerprints on the window and trash bin and quite a lot of skin particles when they went over your clothes. A good labtech should have enough material for analysis (unless they wore plastic overalls, gloves and hairnets).
You might consider investing in a loud alarm siren, though. There are rather cheap systems that are connected with a contact at the window frame. When the window gets opened without switching the alarm off first, a circuit gets closed and the alarm goes off. Hardly any burglar has the nerve to continue his work with such a noise going on.
If you have enough time and money for it, a large dog would be an equally effective solution.