Facebook could tell us how Russia interfered in our elections. Why won't it?

This month, one of the most important intelligence documents about Russian interference in the US election emerged.
Read more: http://www.canberratimes.com.au/technology/technology-news/facebook-could-tell-us-how-russia-interfered-in-our-elections-why-wont-it-20170520-gw9inl?source=Snapzu