Yeah, I have some situation with btckey.space. Owner stole satoshi from my small amount balance which I tested there. I made small research of these 3 sites.  
btckey.space and washen.me have very similar code structure based on Golang. Data generates on server side and user receive one html file with all data. It can be same owner of these sites.  
btckey.online  based on Angular 1.x and Golang. Data received form server-side as json and view generates on frontend side.
 
Source code for backend something like this https://github.com/saracen/directory.io.