Update, 8/28 - 3:15PM - It looks like the account in question is actually restored and functional at this point. The group's last post was about two hours ago.
We reported earlier this week about a collective called Lizard Group that was not only causing some major hassles for certain MMO companies and its players, but also caused a flight carrying a Sony executive to ground due to a hint of a bomb being on board. While this all played out, Lizard Group kept everyone up to date through its Twitter account, which had no shortage of further threats and taunts.
It seemed to take forever, but Twitter has finally taken action and closed down Lizard Group's account. Assuming that the group hasn't grown bored, it seems nothing would prevent it from starting up another account. While no one liked the affect the group has been having on some online games, its Twitter account provided the best heads-up of where it was going to focus its attention on next.
In the time that Lizard Group's Twitter account was live, it enjoyed over 40,000 followers and made close to (or possibly more than) 700 tweets. With that kind of presence, I have a hard time believing the group won't be popping-up again.