Poitras is actually the shadow of this whole story. She was the journalist Snowden reached out to when Greenwald was unresponsive, was there and filmed the first Snowden interviews, was responsible for the Bill Binney story in the NYT a few years back[1] and has been on the US Government shit list for quite a few years[2].
[1] http://www.nytimes.com/2012/08/23/opinion/the-national-secur...
[2] https://en.wikipedia.org/wiki/Laura_Poitras#Government_surve...