How to set up normal camera as a spy camera?

(I have a panasonic lumix something lol)

i have reason to believe that my brother has been stealing money out of my wallet while im at school and i need some way to catch him in the act without actually being there and i was hoping to set up my digital camera as like a surveilance camera for like taking a picture every second and saving it onto my computer

(i would prefer if the method did not require me to buy anything)