Renowned investigative journalist Michael Hastings was working on story about CIA Chief John Brennan at the time of his mysterious death

• Brennan has has been described in secret emails from the President of CIA contractor Stratfor as being on a 'witch hunt' of investigative journalists.
• The day he was killed, Hastings sent an email to his editors alerting them that the federal government was investigating him and interviewing his 'close friends and associates'
• Hastings' widow says she believes his death was probably just a tragic accident