“Hell on wheels” killer Mackenzie Shirilla is nothing like the remorseful, hardened prison inmate depicted in the hit Netflix doc, a former inmate said.
“When she walked out in the documentary, my jaw literally dropped, because her demeanor and the way that she looked was nothing like the person I was in there with,” Mary Katherine Crowder, who served time with Shirilla at the Ohio Reformatory for Women, told The Post.
Instead, the 21-year-old convicted killer glammed herself up behind bars — and pranced around like the queen bee of “Mean Girls,” Crowder said.
She also wasted no time getting busy — and would routinely sport hickeys from hooking up with other women, the former prison inmate claimed.
Shirilla’s parents and sugar daddies she has lured online help pay for makeup and cute fits, she added.
“The Crash” — which documents the case of Shirilla intentionally crashing her car and killing her boyfriend and friend in 2022 — has risen to No. 1 on the streaming service platform since it was released Friday.
Shirilla, now 21, appears in the documentary from behind bars — where she expresses remorse for the fatal crash and insists she’s “not a monster.”
But the person portrayed there is a far cry from the “little high school girl” whom Crowder, 27, got to know while inside prison for more than six months in 2024, she said.
“When I was in there with her, you’d look at her and she had her makeup done every day, she was very well put together — almost like preppy,” Crowder said.
“But in the documentary, she did not look like that at all — she almost looked like she was conforming to the people that have been there for a while.
“Even the way she talks is completely different — she talked like a Valley girl when I was in there with her. Her voice was very happy-go-lucky and high-pitched, but now she has an edge to her voice,” the former inmate recalled.
She added: “This character in the documentary is nothing like who I saw in there at all, and it was shocking.”
When Crowder was booked into the Ohio women’s prison on outstanding misdemeanor warrants from Tennessee in April 2024, she noticed that Shirilla — who had been in the facility for almost eight months at that point — fancied herself a prison celebrity.
“Everyone knew why she was there, and she walked around like she was this famous person within prison,” Crowder said. “She always had makeup done, hair done, her clothes were altered to fit her body tighter or be different.
“She definitely carried herself like she was the Regina George of prison … she was very much like an ‘It girl,’” she recalled — referencing the “Mean Girls” clique leader.
Crowder, who first posted about her history with Shirilla in a now-viral series of TikTok videos earlier this week, claimed in one clip that the teen convict treated the clink “like a high school popularity contest.”
And instead of grieving her friends “every single day,” as she claimed in the new Netflix special, Shirilla spent her days “basically skipping” around the prison yard with a tight-knit group of young inmates, according to Crowder.
“She was always laughing, always smiling and happy — like it was never on her mind that she was serving two concurrent 15-to-life sentences because she killed two people,” Crowder said — adding that Shirilla would sell customized jewelry and shoes to other inmates inside the prison.
“Never one time did I see Mackenzie cry,” the former inmate further claimed in one TikTok video that amassed nearly 20 million views.
“She walked around like she thinks she’s gonna get out.”
Shirilla also cycled through multiple romantic relationships with other female inmates, Crowder claimed in the social media clips.
“Yes, Mackenzie has had multiple girlfriends … she was walking around with hickies on her neck,” she said in one video.
“She’s gone to ‘the hole’ [solitary confinement] for being intimate with girls in prison.
“If she was grieving or remorseful, she would not have gone to prison and jumped into prison relationships over the next six months,” Crowder continued.
Shirilla — whose four-year relationship with Dominic Russo had descended into intense toxicity in the weeks leading up to the crash that killed him, according to prosecutors — was financially supported by her parents and other outside supporters inside prison.
She received new clothes, makeup and other commissary perks ordered through third-party vendors, Crowder claimed.
“Mackenzie has makeup and jewelry in prison because her mom is ordering it for her … she was funding her prison lifestyle and making it as comfortable as possible,” she said in a TikTok clip. “She’s privileged in prison because her mother and father enable that.
“Also, Mackenzie is on the … prison sugar daddy website, so there’s sugar daddies, like, supplying her needs,” Crowder claimed.
The TikTokker also showed wild photos of Shirilla posing and showing off a new outfit in tone-deaf selfie images taken with prison-issued, iPad-like tablets.
“The Mackenzie that I was in there with looked a little bit more like this,” Crowder said in front of an image of Shirilla pursing her lips while wearing a pink T-shirt and purple-and-pink hair clips.
“Very bright-faced, very girly.”
The video then pans to show Shirilla posing in an oversized navy blue top and a slicked-back bun — in a photo “showing her outfit that she got custom-made in prison,” the former inmate said.
Crowder also cast doubt on claims raised in the documentary surrounding Shirilla’s health and version of events leading up to the deadly crash, saying she never observed her seeking medical treatment behind bars.
“Never one time did I ever see Mackenzie Shirilla go for a blood pressure check, take any type of medication or go to sick call, ever experience dizziness.
“In fact, Mackenzie Shirilla would go out in 100-degree heatwaves with baby oil on her and sit in the prison yard and tan … the girl does not have any medical issues,” Crowder claimed.
Shirilla also told a vastly different story to her prison friends than the one painted by prosecutors using blood test results from the night of the crash — which showed that the teen killer only had THC in her system during the grisly event.
