##You can’t publish that story without lawyers involved

You’re not writing a book loosely “inspired by” this person and this event in their life, as in your examples about Severus Snape or The Silence of the Lambs. You are literally writing about a real person, and basing a book directly on their life story and real actions, and directly confirming these matching identities between fiction and real life in your story.

Neither is your story a parody. Nor can just playing up the fictional parts transform a work of fictional history into a parody.

These aren’t legal evaluations—I’m not a lawyer. These are “plain as nose on face” observations from having layman understanding of what you’re proposing to publish.

This is not a character and a plot you can just lift and use directly. You’re either going to have to buy the rights to their life story or get a lawyer—probably both.

You can’t publish that story without lawyers involved

You’re not writing a book loosely “inspired by” this person and this event in their life, as in your examples about Severus Snape or The Silence of the Lambs. You are literally writing about a real person, and basing a book directly on their life story and real actions, and directly confirming these matching identities between fiction and real life in your story.

Neither is your story a parody. Nor can just playing up the fictional parts transform a work of fictional history into a parody.

These aren’t legal evaluations—I’m not a lawyer. These are “plain as nose on face” observations from having layman understanding of what you’re proposing to publish.

This is not a character and a plot you can just lift and use directly. You’re either going to have to buy the rights to their life story or get a lawyer—probably both.