How to recognize/ judge whether the PI/ recruiter has selected me as post doctoral fellow? I applied for a position doing interdisciplinary research work in my field. The PI contacted me, took my interview and told me he would contact me again for my presentation. My interview went for one hour. 

After three months the PI returned and asked me to present my work on Skype. My presentation went for one hour and I answered all possible questions except for my experience with in vivo applications. I answered that being a foreign national I was not allowed to handle in vivo techniques. Finally he mentioned that he would get back to me. 

I am not sure whether he selected me as post doc fellow. How can I recognize if he selected me?
There is a very easy way to recognize when you have been selected: you will get a signed letter offering you the job. 

If you haven't got one, then you haven't been selected (yet). 

Everything else is irrelevant. I can understand that it's tempting to try to guess from subtle cues, but it's really a waste of time.