In revisiting that original story it seems that the best the murderer (Lisa Montgomery) managed was to use a fake name in her Messenger chat. It isn't hard to set up multiple chat identities, but they would still show the IP address unless she knew how to spoof that. Apparently she didn't.

It's probably also a good thing that Stinnett must have had her chat program set to archive the conversation for at least a little while.

SRS