Mackenzie Shirilla Accused of Acting Like A 'Mean Girl' In Prison

Netflix viewers met a remorseful Mackenzie Shirilla in Netflix's "The Crash" ... but a former inmate says the real person -- behind bars -- is far different.

Mary Katherine Crowder -- who spent over six months locked up with Shirilla at the Ohio Reformatory for Women -- has been blowing up TikTok with claims that the convicted killer acted more like the "queen bee" of prison than someone haunted by the deadly 2022 crash that killed her boyfriend, Dominic Russo, and friend, Davion Flanagan.

Crowder told the NY Post that Mackenzie walked around prison like she was famous ... always glammed up and treating the facility "like a high school popularity contest."

Crowder claims Shirilla was constantly giggling, smiling, and socializing with a tight-knit clique of younger inmates ... despite serving concurrent 15-to-life sentences for murder. She also alleges Mackenzie had multiple romantic flings behind bars and frequently showed off hickeys from hookups with other inmates.

The allegations are gaining traction online because they sharply contrast with the image presented in Netflix's new documentary, where Shirilla appears emotional and subdued, insisting she’s "not a monster."

Crowder says Shirilla spoke like a "Valley girl" and obsessed over her makeup and appearance -- carrying herself more like a prison celebrity than a remorseful killer.

Shirilla was convicted in 2023 after prosecutors argued she intentionally drove nearly 100 MPH into a building in Strongsville, Ohio ... killing Russo and Flanagan. She's currently serving concurrent life sentences with parole eligibility in 2037.