Case Update: Stepmother Who Confessed to Suffocation Murder of 3-Year-Old Arianna Stout Finally Sentenced

Arianna Stout
Arianna Stout.

Justice has been served for the callous, wholly unnecessary death of a beloved three-year-old girl with limitless potential.

Arianna Rose Stout, who was born on May 19, 2015, died on March 14, 2019 at Ashley Regional Medical Center in Vernal, Utah, just two months shy of her fourth birthday. An autopsy revealed that Arianna’s death was a homicide caused by asphyxia due to smothering, and in May of 2019, police arrested her stepmother, 24-year-old Mckenley Jordan Yadon-Stout. 

While being interviewed by police immediately prior to her arrest, investigators said Mckenley “admitted to smothering [Arianna] using a blanket on [her] bed.” Evidently, Mckenley admitted she had planned her stepdaughter’s murder for two or more days prior to carrying it out; at the request of investigators, she even demonstrated on a CPR dummy how she smothered Arianna with a blanket from the little girl’s bed and described her “body movements and struggle during this event as she maintained consistent force over [Arianna’s] airway.” 

This cold-blooded woman then waited 10 to 15 minutes after Arianna’s death to call a friend, who called 911 after Mckenley told her that Arianna was choking and became unresponsive. Obviously, when first responders arrived at the Stout family’s home and found the little girl “unresponsive, not breathing, and cold to the touch” with “dark purple and black bruising in front, on top, inside and around her left ear,” according to a probable cause affidavit, “It was immediately apparent that these injuries were not consistent with the details initially provided for the medical response.”

Mckenley Yadon’s booking photo.
(Uintah County Sheriff’s Office)

Mckenley was charged with aggravated murder, a first degree felony, and child abuse, a second-degree felony. In January of 2020, she was found competent to stand trial. Due to the pandemic, her case progressed slowly through the Uintah County court system, but at a hearing on August 13, as part of a plea agreement sparing her the death penalty, Mckenley pleaded guilty to her charge of aggravated murder. The second-degree child abuse charge was dropped as part of the agreement. 

While negotiating the plea agreement, both the defense and the prosecution had agreed to a recommended sentence of life without parole. 

On Friday, December 4, 2020, at a sentencing hearing that commenced at 1:00 PM and took place via video conference, Uintah County Attorney Greg Lamb told the court, “Little Arianna’s life was snuffed out in the most hateful and violent way.” 

Arianna Stout family
McKenley holding Arianna’s baby brother, and Aaron holding Arianna.

Mckenley’s defense attorney, Rudy Bautista, told the Deseret News after the sentencing hearing that Mckenley suffers from several mental illnesses and developmental delays. He added that his client was basically abandoned as a child by her biological parents and subsequently suffered years of physical, sexual, and emotional abuse. 

Mckenley’s fellow inmates in the Uintah County Jail, where she has been held since her arrest in May of 2013, reported that she mentioned being jealous of Arianna, who she blamed for her own death. 

The judge considered multiple victim impact statements prior to the hearing, but only Arianna’s father, Aaron Stout, was permitted to read his statement to the court. He spoke of how his little girl would run to greet him when he got home from work and how she would don his hard hat and say, “Let’s go to work!”

Aaron holding newborn Arianna on May 19, 2015. (Image: Facebook)
Aaron holding newborn Arianna on May 19, 2015.

“I’m just so distraught that someone could be so heartless to take it out on an innocent child,” Aaron said. “I’m trying to move on with my life, but how can you do that when you’re so broken?”

Mckenley declined to speak prior at the hearing.

8th District Judge Edwin Peterson said, “It’s one of the most reprehensible and despicable crimes known to mankind.” However, he also said, “I think we’re dealing with a condition of sickness here in the way somebody would think like that.”

Saying he wanted to allow investigators to decide in 25 years whether Mckenley still poses a risk to society and especially to children, Judge Peterson sentenced her to 25 years to life in prison with the possibility of parole. 

If she is deemed safe to release, Mckenley could theoretically be paroled at the age of 50.

Proud grandma Christina Cook holding Arianna the day she was born (May 19, 2015). (Image: Facebook)
Proud grandma Christina Cook holding Arianna the day she was born (May 19, 2015).

After the hearing, Rudy Bautista told the newspaper that the judge’s decision to permit parole to be considered after 25 years was compassionate, demonstrating recognition that medical professionals could someday help Mckenley and others like her.

It’s an interesting and somewhat surprising take, especially considering Mckenley was found competent to stand trial, which indicated that even if she was mentally ill at the time of the murder, she knew right from wrong. I’d be very curious to hear what her diagnoses were.

On the Justice for Arianna Facebook group, Arianna’s maternal grandma, Christina Cook, posted an emotional video after the sentencing on Friday, saying: 

“Hi, everyone. Just giving you an update. Today we had the sentencing for Mckenley… on my granddaughter’s case. It was a little emotional to hear, especially how she did it and the reason why she did it, so we finally got those answers as to how and why. There’s a lot of mixed emotions between every member in the family. Some of them, it has hit us really hard… and other members, it’s… I don’t think it’s really hit yet. And to those who weren’t able to get onto the WebEx, I apologize. I was just barely able to get on myself. She got 25 to life with parole, but she won’t be eligible for parole until the year 2044, but who knows what will happen in the meantime between now and then. When the judge asked her if she had anything to say, she basically said, ‘No, I don’t.’ 

Arianna Stout
Arianna Rose Stout.

“I wasn’t able to give my victim impact statement. The judge said he had read them all, but Aaron was able to give his impact statement, and I think he did a pretty good job. He got the point across, and he got the point across of how he was feeling and how the family was feeling, and the judge also advised him that he needed to seek out counselling, so I just hope for Aaron’s sake that he does. At least we got justice for our little Arianna. It doesn’t make it any easier with her not being here, especially with the holiday season coming up, especially with Christmas coming up, because it was one of her favorite times of the year… Thank you, and please keep our family in your prayers that we may be able to find comfort.”

Arianna’s father, Aaron Stout, went live on Facebook the following morning, saying, “I just wanted to say that yesterday was a very hard day for me. It was the sentencing for that monster that murdered my little girl. Yesterday was something else. You know, I’m grateful that my daughter finally got her justice, but it should’ve happened a long time ago. All I got to say is, to that monster, you got it pretty damn easy. Do I agree with 25 years? No. You should’ve got life without parole. Not only did you ruin my life; you took away something that I cherished, and that was my daughter. You know, you can sit here and say all you want that my daughter was supposedly the problem, but deep down, Mckenley Yadon, you was the problem. How selfish can you be to take an innocent child’s life — my child’s life and have no remorse? The past two — almost two years has been a living hell for me. I just don’t understand. How can you honestly do something that’s so monstrous to a child that loved you? You are a very sick person. Very. 

Arianna Stout.

“You never deserved to be a mom. I gave you that opportunity to be a mom. I gave you the chance. I gave you a life. I gave you the best life that anybody could give anybody. I trusted you with my kids. I gave you one job, and you couldn’t even do that. I will probably neer understand what truly your intentions were, but it seems like this whole time was nothing but a sick game. You broke me, okay? You broke me… No relationship is worth losing someone you truly care about… My kids have always came first. It sounds like you were a little jealous because I loved my kids more than I loved you. Damn fucking straight, because that’s what a father does.”


He went on for about 40 minutes in the same vein, and I honestly can’t fault him for a single thing he said. I truly hope he’s able to heal and find peace and comfort in his memories of his baby girl.

My heart goes out to the Stout and Cook families and to everyone who loves Arianna. It’s a small comfort to know that, at the very least, she’s been reunited with her loving mother, Jessica.

Most importantly, Arianna Rose Stout will never be forgotten. Rest well, precious girl.

Click here for my coverage of Arianna’s case.

Sources: The Deseret News, Justice for Arianna Facebook group

One comment

  1. Oh my God. I read through the first article here about this beautiful little girl and was just in shock that a stepmother could be so cruel to a child that she supposedly loved and cared for. When I got to that part in the article where it described this stepmonster smothering this precious child… I just couldn’t continue but pushed through because I wanted to know why.

    The fact that this woman admitted that the reason for why she did such a thing to a child is deplorable. She did it because she was jealous? What woman is jealous of a child? Was she jealous that her SO paid a child (HIS CHILD) more attention than her? Was she jealous of the child’s appearance? I mean, come on… this was a child. There’s no competition when it comes to an adult and a child- none whatsoever.

    If she was feeling so much negativity towards a child, she should have just walked away. Just said that she was done because she couldn’t deal with Arianna and whatnot… not plan her murder and then carry it out.

    Child abuse cases/murders always get to me, but the callousness of what happened to little Arianna bothers me especially. Here this little girl thought that she had a loving mother figure in her life- who would step up and love and support her, only for her to turn into such an evil monster. Do you think that if the stepmonster in this case didn’t plan to murder Arianna in this way that there would have been physical abuse and neglect?

    I mean, the stepmonster clearly saw Arianna as a threat to her…

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