In a previous post, I've given a high-level overview of the issues involved in using real people as the basis for your characters. But this raises a very technical issue called libel in fiction. And that can be just as bad as libel in fact.
Here's three steps to consider if you want to take a real person and use them as the basis for a character in your fictional universe:
Step 1: Think of what needs to remain and what can change. If you are going to use an exact clone of a real person, you need to get their permission to do this through a name, image, and likeness release (I'll write about these in a future post). But you can often adapt a real person into a fictional character if you do it right.
This shouldn't be surprising. There are very few truly impossible-to-replicate character descriptions you can write outside of a sci-fi or fantasy setting. So nearly all of us could find many of our personality traits mirrored in someone's fictional characters. If just having a character who resembles a real person was enough to cost you a lawsuit then every author would be breaking the law.
At the Game Developer's Conference in 2006, I saw Ron Moore (the Executive Producer on the Battlestar Galactica reboot) give a fascinating presentation on making adaptations of pre-existing IPs. Using the example of the Starbuck character he walked through the thought process of what you keep and what you don't, to end up with the essence of the original character in a new form and format. Would it really change if you made your main character from a man into a woman? If so, would those changes maybe make a richer story? Asking yourself questions like these might help you start thinking about how best to work through this step.
So what do you need to change?
Step 2: Make sure that you don't just make negative changes. You need to make sure that you don't just make changes that, if you said them about a real person, would be libel.
In Muzikowski v. Paramount Pictures, Paramount made a film based on the story told by Muzikowski in a book he wrote about his experiences coaching baseball in the inner city. It wasn't presented as an adaptation of his book, just based upon it. Muzikowski sued, claiming that he was defamed by the character in the movie that was based upon him.
The court disagreed. Looking at the movie-Muzikowski and comparing him to the real person, the court found all sorts of non-defamatory distinctions between the two characters. For example the character in the movie had children of his own, while Muzikowski didn't. The court held that distinctions like these meant that the adaptation was permissible, because the adaptation wouldn't cast Muzikowski in a negative light.
However, if the only changes were ones that would be defamatory if said about a real person then the court would have found libel. So if you base your child molester character on a real person, make sure that's not the only difference.
Step 3: Think about what a third party who doesn't know these people would think. That's the proper question to ask.
Tamkin v. CBS Broadcasting is a case about a LA real estate broker couple, Scott and Melinda Tamkin, who sued CBS over being included in an episode of CSI. In the episode a mortgage broker named Scott Tucker (their last name was changed during editing) is said to be into bondage and porn and is thought to have killed his wife, Melinda, during a particularly rough bout of sex, but really she killed herself and framed him.
The Tamkins had been working with a writer for CSI on finding him a house, and when they watched the episode they felt they recognized several of their own personality traits in there: Melinda Tamkin was a runner just like Melinda Tucker, and both she and Scott Tamkin and Tucker used prescription toothpaste. In fact, in the original draft of the script the characters were named Tucker, but they changed the name to Tamkin before filming.
That sure sounds like the Tuckers are the Tamkins, and you'd think the Muzikowski case would be pretty important here to say that CBS shouldn't have let these characters into the episode.
You'd be wrong.
The legal test isn't whether the person on whom you've based the character would recognize themselves, or whether their friends would. It's whether a reasonable person hearing the descriptions of each group of people would think the characters are based on the real people. That's a big difference and so the court held that the portrayal of the Tamkins in the CSI episode wasn't libel.
Truthfully, based on this case I don't really know where the line is any longer. If you can take a person's somewhat-distinguishing personality traits, add a dash of bondage and porn, and then it's okay so long as you change their job... So Tamkin feels like something upon which you maybe shouldn't base all of your characterizations. A safer way would be to use the Muzikowski standard and add a few neutral and positive changes as well as the ones that might make your character more interesting. But either way, you probably have more leeway than you thought.
Muzikowski v. Paramount:
Tamkin v. CBS Broadcasting: