and we began to hear about it from the ground up that bob had this special source. >> when will the rest of the world know who is deep throat? >> when that source passes away or releases us from our agreement and pledge of confidentiality. >> who is deep throat? >> we said deep throat is a man. >> you can rule out some suspects like diane sawyer. woodward says deep throat was a man. >> you build a strong case for the identity of alexander hague. >> do you have any idea what deep throat was? >> deep throat is a collection of people. >> how did the secret of deep throat last for so long? the answer is, neither of us told our exwives. >> during our filming, woodward mentioned the portrayal was close to the real thing. when i asked him who the man was, he just smiled. >> other guesses over the years, john sears, mark felt.