They are most likely to be a bug, scrapers or bots.
This is not the first time others have raised this topic:
The forum stats are wrong! @theymos check it out,please."Total time logged in" bug and accounts with long time logged in~~~
I will investigate the alt of these accounts. If they are involved in any illegal activity I will find out and take strict action against them.
LMAO, your post really made me laugh. Did you even bother to think your post through before clicking the "post" button? dude those accounts have zero posts and you want to investigate them, how and what exactly will you be investigating?