Liz emailing as Amy question...

So it was pretty difficult to catch Liz in the outset cause she knew how to use VPN and stuff. They had to get a tech guy to track down IP addresses. Ultimately, everting points towards Liz and she's being interrogated in a friendly manner, to make her think they believe her story. What boggles my mind after this is that she starts to fake emails as Amy. They didn't go into it, but I assume she created emails as Amy, then wrote to herself, then forwarded to the police. How did this person go from understanding VPN and computers, to doing something so amateurish? Amy could easily prove she didn't create those email accounts, nor wrote those emails. The police could easily figure it out too. You would think Liz would know this, wouldn't you? So I surmise Liz might have been a computer illiterate all along, and simply got lucky with the VPN covering her tracks because maybe the VPN happened to always be on when she was writing and texting from her boyfriend's home. Otherwise, I don't understand how the same brain can go from understanding the need to hide online digital footprint, to something so amateurish as creating fake email accounts.