Originally Posted by
SteveB
That may give you the IP address.
To get an actual address is much harder and would, most likely, need access to the internet provider’s logs.
Most IP addresses are dynamic, that is they change. So you need the IP address, but the exact time. Although the logs are likely to be accurate, they are not accurate enough to be used as evidence. And knowing an address is not proof of who was using the computer.
As has been mentioned by other posters ( drbagehot and gonzo) it is stupid to be complacent, but I still think the simple, (relatively) cheap and low-tech (and low IQ) method is just to stake out some well-know and over-used location.