I need some kind of spy gadget for the door of my flat....?

I live in a flat in my block there is 4 floors, 2 on each floor. The floor opposite me has been broken into twice, im scared that im going to be next as I am away alot. Is there any kind of device i can put outside my door in the hallway/landing to keep an eye out? and thing that i can disguise and somethin that records videos like 24hour or somethin. Preferably something small, i know theres peep hole cameras but im not sure they record or how to record footage of them?
Our security door at the bottom doesnt lock and i have been on the phone to my factors twice now,
my door and the other flat door are 2 metres apart, i feel that putting a full size camera would really attract attention and may start something