Who is the "SITE Intelligence Group" and who is the "Islamic State" if mentioned agency didn't manage to come even with the name of the SINGLE individual/department/organization for whom they claimed have assumed responsibility for Vienna attack on behalf of "Islamic State"

Anonymous messaging system in hands of totally unknown agency is now a source of government information according to which citizens of the world should have their leaders base their war decisions upon !!??? Source: https://in.news.yahoo.com/islamic-state-claims-responsibility-vienna-225447616.html

I would think if we are talking about state of any kind, they would have their speakers/people/ representative explain who/what why...no !!????

No man because its easier to have two "investigators" send message to one another and assume attack claim on someone else's blame. 

SITE Intelligence Group = George Bush's basement.

Clearly is indifferent from