How to mass remove users from one domain
 

Hi, A while back I was hammered hard with spammers. So I now have a few thousand 'users' that aren't actually users. I'd like to remove them but can't figure out how.

I've come to learn that a large amount are .ru addresses. I can search for .ru under search for users in admin, but that only allows me to delete one-by-one. Prune/Move Users on the other hand doesn't allow me to search for users based on domain.

Does anyone have any ideas how I can go about this please?
Thanks in advance