Prolific U.S. documentarian Alex Gibney has tackled such topics as Scientology, Wikileaks, sports doping and the pedophilia scandal that shook the Catholic Church. His latest film, “Citizen K,” which premieres in Venice on Saturday, delves into the case of Mikhail Khodorkovsky, once one of the richest men in Russia.

After challenging Russian President Vladimir Putin, Khodorkovsky served a decade in prison for what critics say were trumped-up charges of tax evasion, and became a world-famous political dissident. Gibney spoke to Variety about how the surprising journey of this oligarch provides a prism through which to look at Putin’s iron fist.

What drew you to the subject matter?

I’ve always been interested in power and the abuse of power. Khodorkovsky understands power in Russia better than almost anybody, having been at the top and at the bottom. For those reasons it seemed really interesting to be able to make a film about him, particularly if he was willing to sit for an extended session of interviews. We are all interested today in the nature of power in Russia. Who better to help us understand this than Khodorkovsky?

Khodorkovsky comes across as a stoic. His human side seems rather impenetrable. There are some personal details in the film, but not many. You sense that he’s steering clear of some things, such as talking about his family.

I decided in the end not to delve too deeply into the area of his family for a couple of reasons. First of all, I think for self-preservational reasons he’s kept his family out of it, mostly. You can see bits and pieces, and get a sense of how hard it must have been to have your kids grow up while you were sitting in prison….You’re right, he’s a tough guy. He doesn’t betray very much. He’s not Oprah. He’s not going to open up in that kind of a way. I think there’s a reason for steering clear of getting too involved in his family, in part because they may still be at some risk. By and large we kept the discussion on his personal journey and the insights he has on power in Russia.

How did you feel about this issue? Did it ever cross your mind that there could be a security risk for you?

It did cross my mind. I got a visa which allowed me to operate on a business level in Russia. They certainly knew I was coming. I was coming wide open. We took the usual precautions for Russia, which has so much malware you need a raincoat to protect yourself…I would not say that I felt the kind of intense scrutiny that you do feel in China when you go there. I calculated that being open and transparent was the best policy.

Did you try to get archive footage from Russian sources?

We tried. I would say that the archive material that’s included in the film is a combination of archive material and fair use. We weren’t always granted permission, and there are some key pieces of footage that we would have found very useful — notably the unedited version of a famous televised meeting between Putin and Khodorkovsky — which we asked for and never got permission to get. The official Russian archives were not welcoming to us. 

Is there any chance that “Citizen K” will be shown in Russia?

I sure hope so. It will be interesting to see if it will be, and I’m hoping to test the limits.

You did two rounds of interviews with Khodorkovsky, the second one after having gone to Russia. Did that give you more insight?

It was hugely valuable to do that second round because at that point I had a better relationship with him, but also because I had a better sense of how he is perceived in Russia. With the exception of a small group of activists, I would say he is largely reviled….He represents this kind of stereotype of the evil oligarch who raped Russia during the ’90s. And Putin very much lives off of that idea that he’s bringing order into the chaos that the oligarchs engendered. Of course, Putin has established his own version of that same system. But that’s the great irony of how information and fake news works in Russia. 

Do you think that with this documentary Khodorkovsky will become more secure?

It’s hard to know. I think there is a pretty good argument that the more public you are, that does afford you a kind of protection. I sometimes operate that way as well. That said, I think that the way that assassinations of people who are critical of Putin works is that sometimes people who feel that they are doing the will of the boss decided for one reason or another to lash out against people who are perceived to be critics.