ISIS Twitter accounts have been linked back to the United Kingdoms Department of Work and Pensions (DWP), and the UK has admitted to selling the IP addresses to Saudi Arabia, which is where the addresses where traced back to following the sale from the UK, yet they deny any responsibility to actions taken via the specific addresses.

http://www.mirror.co.uk/news/technolo..., http://www.zerohedge.com/news/2015-12..., https://www.rt.com/uk/325994-isis-dwp...