I thought lulzsec said they were done after their 50 day mission? Guess they had to come back for this.
Edit: Though, looking at the screenshots of the tweets on the TechCrunch page, they don't actually explicitly say it was them.
Edit 2: They did claim responsibility for it (just not in the tweets TechCrunch took a screenshot of).
I think it's pretty safe to say that they're both controlled by LulzSec.