I know we are not supposed to report spammers and just let them do their damage until spambrainz is ready, but I’d argue that trolls are different. Their aim is not to leave some spam here or there, but to wreak havoc.
It seems like they are hacking into old - never really active - accounts whenever another account gets exposed.
These are the ones I found so far:
I have no idea how, but they must be stopped.