Scarey stuff indeed! He/she was probably just checking how many people were in the house before proceeding to rifle the joint - thank god you woke up. I always keep the doors locked when I am home alone through the ay - luckily we have a goo security screen door on the front but the back screen doesn't lock so I can't have that inner door open.

And I hate to be a doom sayer but this person has now eyeballed all your stuff - be extra vigilant for a few weeks as they might come back with friends. I do say might, the noise and presence of Police will most likely have scared them off permanently, but be carful.