Waterworks wrote:
It would depend on the type of vpn used, if it was a free one they are often terrible because they are not spread over a large network and often drop out. If they do drop out it would show something like a connection from an ip in China, a connection from an ip in Carlisle Cumbria, then when the vpn came back on a connection from a new random ip, usually no location is damming but in this case it would be as we would have an ip from which we can see the actual location and type of connection ( Carlisle Cumbria )The free vpns also don't always have great encryption.
The paid vpns are spread over a larger network and often have very secure end to end encryption, they are not always impossible to trace if a person or company has technical tools and knowledge at their disposal but it's certainly difficult and in some cases impossible to pinpoint a definitive location and information.
The good thing about this case is all of the login data is known to AB, so if he doesn't normally use a vpn for Twitter ( which would be strange if he did ) we will have good source data, IE logins from the same ips on multiple occasions even if there is 3/4 of which we can trace the location of, if during the malicious login there was a random ip it would be strong evidence of innocence unless he was wise enough to login with a vpn on only that occasion. If however he used vpns a lot then it gets pretty difficult to prove guilt as there will be many different ips and it wouldn't surprise me if this defence was used, however there are tools to separate real ips from vpn networks and so forth which I'm not going to go into.
I really don't see why he would use a vpn though unless he planned to stage a hacking which would just be weird. The good thing is none of his previous login data can be changed so if we ever see that information it would be clear as day with no vpn useage.
There are other methods used to mask the true origin of a users ip and location but I very much doubt they will be at play here.
I used a cheap one for 4 quid a month in Germany like to use bbc I player etc, used to not be able to go on bet365 when I was using it - it's banned in some nations like but not Germany but they must have been able to tell a vpn was being used and have a policy where they block access to the site by anyone using one.
Amazing really what they can tell about you, would have thought this would be a cakewalk like to prove it wasn't him if his claims were genuine.