She was portrayed as inherently dark and deeply disturbed, and the poems she wrote did nothing to divert the narrative.
She described herself as a "horror fanatic" and a "psychopath in the dark" in a blog she labelled Nightmare and penned under the moniker "Vampchick".
On March 2, 2015, five days before doing the unthinkable, 16-year-old Ashlee Martinson wrote a particularly grim fictional account of a gruesome scene.
"Rushing through the woods late at night. Deep into the darkest corner where the agonising screams cannot be heard. Walking into a small cabin. Marveling at the sweet horrors of blood that I thirst for. I then take the next victim who is unconscious. I tightly bind them to a low table.
"Awaiting them to wake once more. I clean the dry blood off my tools from a previous session. The last body has been disposed of just hours before, yet I have not been satisfied with the pain, agony and blood. I bend down as they start to wake.
"'Welcome to hell,' I whisper in her ear. 'Never again will you see the light of day'."
Martinson followed through with the fantasy the day after her 17th birthday, on March 7. On that day she pointed her stepfather Thomas Ayers' shotgun at him and fired once. Ayers tried to grab the gun from her, but she fired another shot at his head at close range.
The teen then ran downstairs at the family's home in Wisconsin and used a kitchen knife to butcher her mother, Jennifer. She stabbed the 40-year-old 30 times.
For the first time since she was sentenced to 23 years in prison, "Vampchick" has told her story. In a prison interview with Crime Watch Daily, which aired Tuesday in the US, the now 19-year-old declares she's not the person people think she is, that she's not the dark character she writes about online. Instead, she claims she's been misunderstood.
"I'm not a monster, I never meant any of this to happen," the now-19-year-old said.
"It doesn't make it right, but I was just a girl, an abused girl who was forced to make a really bad decision. I'm not the monster they portrayed me to be."
The abuse she speaks of is alleged to have taken place over a number of years. In police interviews, she told officers her mother's boyfriends treated her with contempt.
She said one raped her and stubbed a cigarette out on her when she was just nine years old. She said her mother failed to intervene.
After shooting her stepfather and stabbing her mother to death, Martinson locked her younger sisters in a bedroom. Later, she said she felt free for the first time. In an interview room, she hugged an investigator and cried loudly.
The day before the killings, Martinson wrote about her stepdad on Facebook.
"I woke up this morning to my stepdad beating my mom ... I can't take it anymore, he's gonna kill her if she doesn't leave soon and I don't want to be around when that happens."
Describing the killings from the Taycheedah Correctional Institution, Martinson said she was trying to protect herself at first, but then she started thinking about all the pain she had endured.
"It was like a movie reel went off inside my head. It was like a flash of an image. Memories of all the bad things that happened to me, that she put me through. I remember stabbing her once ... then twice ... then I blacked out and the next thing I knew there was blood everywhere."
Martinson says she does not regret her crime. She knows people will struggle to understand her motives, or how she could snap the way she did. Not even her siblings understand why she did it.
In a letter written shortly after Martinson's sentencing, her sister wrote: "I think she should stay in jail until she rots."
Martinson responded in a letter to the judge.
"Even though I have made my sisters into orphans, I know deep down that they are now in a more safe and loving environment. I hope that one day they will be able to forgive me."