--London Metropolitan Police Deputy Assistant Commissioner Steve Kavanagh, paraphrased with regard to containing the riots in London
Also,
"Social media and other methods have been used to organise these levels of greed and criminality."..."That investigation is already under way and that is exactly the sort of thing we are looking at," he said.
My colleague Helen Popkin reminds me that being arrested for a tweet is not entirely unprecedented, but for social media observers it's interesting to watch the virtual social space lose its novelty and become integrated enough with crowd dynamics that virtual participation in a riot is tantamount to real life participation in a riot.
(Not really related but since I have this tab open as well and hey, how often do I get to blog about getting in trouble for tweeting: What journalists need to know about libelous tweets)