Toddler thrown out with the trash, burned with a blowtorch. Shocking new details in arrest of accused child killer.

Source: Laramie County Sheriff's Office; Cheyenne police

Aug. 5 2021, Published 2:26 p.m. ET

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On the afternoon of Feb. 19, a mother called 911 to report her 2-year-old son missing.

She hadn’t seen Athian Rivera, of Cheyenne, Wyoming, since the night before. Athian couldn’t get down the stairs on his own, either, she said: the family—she, her boyfriend Wyatt Lamb, and her two other young children—lived on a second-floor apartment.

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She’d already searched, but 911 she was very worried.

When police arrived at the apartment complex shortly after 1 p.m., they searched inside, then began scouring the immediate area. Within an hour and a half, they located Athian’s body, still warm, in a dumpster. He’d been wrapped in several trash bags, a sheet and a blanket.

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An autopsy the next day revealed the toddler died from lack of oxygen to his brain, or blunt force trauma causing brain swelling, or both.

Police suspected her live-in boyfriend immediately, but forensic testing and examination of Athian’s body told a darker tale of what occurred before the child was murdered.


Kassandra Orona, Athian’s mom, went into work on her usual graveyard shift at a sandwich shop the day before. Typically, she left Lamb in charge of the three kids, who usually slept in the same bed. Osona drove to her job a little before 5:30 p.m. and returned home at 3:30 a.m.

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The kids were asleep when she returned and, not wanting to wake them, she went to her bedroom. She and Lamb smoked weed for the next hour, according to court documents, until they both fell asleep.

Around 8:30 a.m., Lamb woke her to help take the oldest child, who was running late, to school. They got in the car and drove her daughter a short distance down the street to drop her off, leaving the two boys at home. Returning within a few minutes, she later realized that Lamb was trying to keep her from checking on Athian, according to Oil City News.

After getting back home, Orona and Lamb smoked more weed, and she fell asleep, assuming her two boys were asleep, although she hadn’t seen them in the light of day.

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She noticed later that Lamb had been acting “nicer than usual” and reported this to authorities, according to court records.

Osana went back to bed around 9 a.m.

As she lay in bed, she heard Lamb opening trash bags and remembered him telling her he planned to take care of chores.

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Around noon Orona was again awoken by Lamb, who now told her he couldn’t find Athian and was worried the child had left the apartment, according to the report. Lamb led her to the front door, which was slightly ajar.

First, she searched the whole apartment. Beginning to worry, she asked both the maintenance manager and property manager for help and began looking outside.

Orona still didn’t understand how the 2-year-old could’ve gotten outside. Detectives later interviewed the men who helped her search, who reported Lamb acting unnaturally. The boyfriend seemed unconcerned, ready to ride off on his bicycle, despite the obvious crisis unfolding. By now, it was nearing 1 p.m., and Orona finally decided she needed help from the authorities.

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She dialed 911, a job she had to do since Lamb had an outstanding warrant, according to the report. Once she called, Lamb left the area to avoid interacting with police. Despite this maneuver, Lamb showed up that afternoon and sat down with detectives for an interview.

Athian’s body had just been pulled out of a dumpster that was within the line of sight of Orona’s apartment, according to the report. Lamb kept glancing in that direction.

He explained he was her boyfriend, but didn’t live there. As he spoke, police noticed he kept looking out the window. Despite his nervousness, Lamb began to account for his activities the day before. Detectives inside asked questions and took notes, while authorities in the parking lot were securing crime scene evidence.

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Most of the details Lamb gave police lined up with what they’d heard from Orona, but the tiny holes in his story began growing the more he talked.

The night before, while Orona was at work, Lamb said he’d put the kids to bed around 8 p.m. During the night, he noticed Athian vomiting, so he sent a Snapchat message to Orona to let her know. She responded by saying if it didn’t improve, they should take the boy to the doctor.

child killed

Court records indicate Lamb told police he last checked on the kids again around 10 p.m.

When Orona got home from work, he said he returned to his house, which he told them he shared with a roommate.

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According to an affidavit, Lamb reported he’d spent all morning at home, sometimes texting with Orona. He claimed he was awoken about 11:30 a.m., when Orona called to tell him, “Athian is missing.” He then explained he’d taken a taxi to get back to Orona’s, since his roommate wasn’t around, and he had no vehicle of his own.

He remembered the cab company: “Classy Taxi.”

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It didn’t take more than a few hours for the police to punch holes in the story and discover the truth. The first problem was he’d was legally bound to stay away from Orona. Yet, he moved in with her six months after a court order that, based on past violent behavior, prohibited such a move.

The 27-year-old was taken into police custody at 6:15 p.m on the prior, unrelated charges. On Feb. 23 he was officially named as a suspect in the death of Athian, according to The Wyoming Tribune-Eagle.

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Lamb’s alibi didn’t hold water for several reasons. First, there was no such cab company as “Classy Taxi.” When detectives tried to find a record of any cab ride for Lamb on the night of Feb. 18 or the early morning hours of Feb. 19, the records didn’t exist.

Digging deeper, they discovered Lamb no longer lived at the address he’d given and had no roommate. His whereabouts during the night could not be corroborated. The evidence they found in the dumpster pointed to homicide, and it didn’t take long to connect Lamb to the crime.

Athian’s body showed signs of torture and horrible death.

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When police looked inside the apartment dumpster, they found five black, thick garbage bags knotted tightly. Inside, a blue and white bedsheet and a blanket wrapped a small form—the body of Athian, who was bruised and beaten. They estimated the time of death to be between 11 a.m. and 1 p.m.—just a few hours before he was recovered.

Authorities sealed up the whole dumpster and transported it back to headquarters for additional forensic analysis.

What authorities found when they unwrapped the bags and sheet was horrifying.

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The Laramie County Coroner’s Office conducted an autopsy on Feb. 20 and reported the cause of death, suffocation or strangulation, as well as detailing the injuries Athian suffered.

The 2-year-old was burned on the lower half of his body, probably with a torch. He had old injuries, including scrapes and cuts and bruises, as well as new ones, all over his body, investigators noted. He had burns to his inner thighs and evidence of “thermal injuries” to his genitals.


Lamb was under conditions from a separate criminal case of March 2020 to not get within one block of Kassandra Osona’s home. In August 2020, according to Orona, he moved in with the family.

Detectives acquired a search warrant for Lamb’s actual residence and located a butane torch among his possessions during their second search of his premises. The court affidavit pinpointed DNA evidence in Athian’s diaper matching Lamb.

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Orona confirmed that the two adults used the two-burner blowtorch frequently to smoke marijuana, according to Oil City News.

Additional circumstantial evidence was overwhelming, including Lamb’s inconsistent statements to police and the fact that he fainted to the ground during his initial interview—the one where he couldn’t stop at the dumpster. He was transported to the hospital before his arrest that day.

The suspect’s fingerprints were also found all over the trash bags that wrapped Athian’s body.=

On June 29, Wyatt Lamb faced an initial hearing at Laramie County Circuit Court, in which the charges against him were read aloud: 10 counts of felony child abuse and one count of first-degree murder. His preliminary hearing is scheduled for Aug. 6.


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