A former friend of convicted “Hell on Wheels” killer Mackenzie Shirilla has described a childhood marked by permissive parenting, emotional volatility, and a household dynamic she claims allowed the teenager to dominate her parents long before the deadly 2022 crash that killed two young men in Ohio.

Jaina Maynard, who met Shirilla in middle school, told The Post that Steve and Natalie Shirilla were more focused on maintaining their daughter’s approval than enforcing boundaries or discipline.

“From what I see, they didn’t really care about her. They cared more to have her approval,” Maynard said. “Kenzie runs the show — she runs her parents. They shouldn’t have been her friends. They should have been her parents.”

Shirilla, now 21, is currently serving two concurrent sentences of 15 years to life in an Ohio women’s prison after being convicted in 2023 of murdering her boyfriend, 20-year-old Dominic Russo, and their friend, 19-year-old Davion Flanagan, in a high-speed crash.

Maynard claims that what unfolded in 2022 was not an isolated breakdown, but the culmination of years of unchecked behavior, enabled at home and reinforced socially.

According to her, Mackenzie frequently behaved in ways that blurred traditional parent-child boundaries, particularly with her mother Natalie, whom she described as overly permissive and emotionally reactive to her daughter’s demands.

“Mom kind of seemed like one of the girls,” Maynard said. “She didn’t seem like a full-on mom. She felt like one of our friends.”

She alleged that Mackenzie often took advantage of that dynamic, treating her mother with open disrespect in front of peers without consequence.

Maynard recalled one incident during eighth grade when Natalie was driving a group of girls, including Mackenzie, to a haunted house.

“Kenzie said word for word: ‘Mom, shut the f–k up.’ And guess what? Her mom shut the f–k up,” she said.

According to Maynard, the moment did not escalate into punishment or discipline. Instead, she said, Natalie quickly returned to acting warmly toward the group as if nothing had happened.

“She was so, so nice after Kenzie just treated her like utter s–t,” Maynard said. “Whatever Kenzie says, her mom just does.”

She further alleged that Mackenzie would frequently insult her mother behind her back, using harsh language while speaking to friends.

“Her parents have done everything for her since she was a little kid, and she’s just badmouthing her parents every chance she can get because they won’t buy her the next collection of Bape hoodies,” Maynard said, referencing high-end streetwear brands popular among teenagers.

“That’s the reason her mom was a bitch,” she added, describing Mackenzie’s alleged comments at the time.

Despite what she described as ongoing conflict at home, Maynard said Mackenzie always appeared well provided for materially.

According to her, the teenager regularly wore expensive clothing, designer shoes, and carried luxury-style accessories funded by her parents.

“Obviously her parents gave her everything,” Maynard said. “Until she started dating Dom, and Dom ended up providing for her.”

She characterized Mackenzie as “the definition of a spoiled brat,” arguing that entitlement and lack of boundaries shaped her behavior long before the fatal crash.

Shirilla’s case has remained in the public spotlight since her conviction, especially after the release of the Netflix documentary “The Crash,” which revisited the events leading up to the deadly incident.

Prosecutors at trial argued that Shirilla intentionally accelerated her Toyota Camry to nearly 100 mph before slamming into a brick building in Strongsville, Ohio, without braking.

The crash killed Russo and Flanagan instantly, according to court testimony and vehicle data that showed the accelerator fully depressed in the final seconds before impact.

Her defense, however, has maintained that she suffered from a medical condition that may have caused her to lose consciousness behind the wheel, though that argument was rejected at trial.

Maynard also alleged that Shirilla’s behavior extended beyond her home life and into school, where she claimed the teenager engaged in bullying and emotional manipulation of classmates.

She described incidents in which she believes Mackenzie targeted other students socially, contributing to a toxic environment among peers.

“It got to the point where this girl ended up checking herself into a mental facility and then left the district of Strongsville altogether,” Maynard said. “It was horrible.”

She also claimed that substance use was visible among some teenagers in their circle and that Mackenzie’s parents were aware of aspects of her behavior, including alleged marijuana use and risky driving.

“Her mom literally follows her on social media and Kenzie would post this freely,” she said.

Maynard alleged that videos of drug use were sometimes shared publicly by Shirilla during her teenage years, though these claims have not been independently verified.

She also dismissed rumors circulating online that Dominic Russo was involved in drug dealing, calling them “completely false.”

Steve and Natalie Shirilla have previously defended their daughter publicly and expressed disagreement with how aspects of her story have been portrayed in media coverage and documentaries.

In the Netflix film, Steve Shirilla acknowledged knowing about his daughter’s marijuana use, stating he did not view it as unusual among teenagers.

“I knew she was smoking dope — I don’t have a problem with her smoking dope,” he said in the documentary. “If you’re going to smoke a drug, that’s the one I believe you should take.”

That comment later drew criticism and contributed to scrutiny of his role as a parent, including questions raised about judgment and oversight during Mackenzie’s teenage years.

Following public reaction, Steve Shirilla reportedly faced professional consequences at a school where he worked, amid concerns over his remarks in the documentary.

Maynard, however, said she believes the broader issue extends beyond one comment or one moment, pointing instead to what she sees as a long-standing pattern of permissiveness within the household.

“They knew what was going on,” she said. “They saw it, and nothing really changed.”

She also claimed Mackenzie’s behavior escalated over time as she gained more independence and influence within her peer group.

Shirilla’s relationship with Russo, according to prosecutors and testimony presented at trial, became increasingly volatile in the months leading up to the crash.

Messages presented in court showed emotional distress, arguments, and instability in the relationship, though the defense argued these did not prove intent to kill.

The jury ultimately rejected claims of accident or medical emergency, finding Shirilla guilty on all counts related to the fatal crash.

Despite her conviction, her legal team has continued to pursue appeals, arguing that evidence of a possible medical condition was not fully explored during trial proceedings.

Meanwhile, public attention around the case continues to grow, fueled by documentaries, interviews, and new commentary from people connected to Shirilla’s past.

As for Maynard, she says her perspective comes from witnessing years of behavior firsthand during adolescence, long before any legal proceedings began.

“The person everyone sees now didn’t just appear overnight,” she said. “It was always there, building up.”