Even though MSM is playing up the dating website angle (of course, as it makes it all more sensationalist) I don't think we should underestimate the whole 'ad on Gumtree' part.
Shey was obviously an intelligent woman - it seems more likely IMO that she would more readily allow someone into her home who is answering an ad to share the house with her. Of course then, you would welcome them in!
I also wonder why, after 4 years living there by herself, she was suddenly seeking a flatmate? For some reason that fact has stayed with me (although it may have nothing to do with anything!!).
If it was from a dating website, we can't assume it was the first time she met the guy. He may well have been grooming her and winning her trust over some period of time. It doesn't mean she just met him and let him in.
Many unanswered questions with this case, obviously. Hopefully LE have a clear picture of who the likely suspects are.
Blessings to Shey and her family at this terrible time.
BBM
I agree Isisrising - it's just as likely that it could have beeen some weirdo who read the ad on Gumtree.