Tim Roth was left horrified when doing his research for 'Rillington Place'.
The 55-year-old actor portrays serial killer John Christie - who murdered eight women and stashed their bodies in his home - in the new BBC drama and admits he was appalled by the crimes.
He said: "I did a stack of research. The production company sent me a vast amount of articles that had been written about Christie, transcripts of the trials, autopsy reports, statements from work colleagues, friends and neighbours and a lot of pictorial evidence - I kept it on my computer so my wife wouldn't have to see it lying round.
"You piece this together and you start to come up with an interpretation of what he might have been like. And as all this came trickling through, I did think, 'My God, what have I got into?'"
Each episode of the show follows the story of a different person, including Timothy Evans (Nico Mirallegro), who lived above Christie and was wrongly convicted of killing his wife Beryl (Jodie Comer).
And Tim thinks some of the footage for his own episode was "too disturbing" for broadcast and has been left on the cutting room floor.
He told RadioTimes.com: "The last one is Christie's own perspective on events - the idea was to show exactly what he was.
"But I think it might have been a bit too disturbing for some at the Beeb. We did shoot some very difficult stuff, and I'm not sure all of it made it to the final cut.
"It's one thing to read a scene on the page, but it's another thing to see it on screen once you've shot it."
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