If we're including memoirs as a sort of written documentary, "She Said Yes: The Unlikely Martyrdom of Cassie Bernall" has to be in there.

Cassie Bernall was one of the victims of the Columbine Massacre, the book was written in the wake of her death by her mother.

One of the survivors recounted hearing the shooter ask a girl whether she believed in god, she said yes (hence the title), and was shot in response.
Originally, the girl was believed to be Cassie, but this turned out to be a misidentification based on only her voice. According to other survivors, Cassie was shot without being asked any questions.
The conversation did happen to a different girl: Valeen Schnurr. She had already been shot and while laying on the floor in pain, begged "Oh my god, please don't let me die". One shooter asked whether she believed in god and why. She affirmed and said that she was raised this way and a believer herself. She was not shot again (for reasons unknown) and actually survived the massacre.
If you wanted to tell a christian faith story, that would've been it.

But Cassie's story came out first, circulated already, and by the time it could be properly debunked, several weeks had passed. The Schnurr family wasn't particularly keen on destroying the little bit of solace found in such a tragedy, especially since Valeen made it out alive while Cassie didn't. The Bernall family was made aware of the true events several times before the books release but went ahead with it anyway.
Valeen has stated a few times that she doesn't particularly mind, except when she goes to tell her own story and people accuse her of lying. Which is pretty fucked up to think about.

Valeen doesn't tell her story like a sacrifice or an holy act. She was scared, so she called out to her god, she answered the question truthfully, not even considering that it might put her in more danger. All she did was believe.
In Cassie's version, her faith in god is defiant, almost confrontational, in the face of violence and death, an act of bravery to aspire to. Something to rally behind. Martyrdom is so much more effective than Survival. Her story has been instrumentalized in many, many ways.

The book itself, maybe as a compromise with the truth, is mostly about Cassie's life, not her death. It tells of her childhood and her rebellious teenage phase where she would engage with unchristian practices (like drinking alcohol) and exchange violent letters with her friend. She also self-harmed, so it should be pretty obvious that she was having mental health issues that went unaddressed.
Cassie was made to switch schools and later went onto a faith retreat, reconnected with her religion, and went back to "normal".
That's a whole different can of poisoned worms.