Three servers used to run 10 Tor exit nodes went down last Thursday. The servers were used as exit nodes, 10 in total. Tor Project believes they were taken down by law enforcement officials. The Tor Project will soon release further information about the takedown and probable explanations. At the time of writing all of these relays should already be blacklisted and not able to rejoin the network. We will not reuse the server hardware in case they become available again. We advise you to not use them in case the servers come back.”]
Source: https://blog.torservers.net/20141109/three-servers-offline-likely-seized.html