In the early morning hours of Sunday, Nov. 25, Autumn Rivera texted her sister to say she and her boyfriend were on their way home from a club — and were fighting again about their relationship.
On the morning of Nov. 27, the sister reached out to Rivera’s boyfriend, Jonathan Akin, to ask what was going on and why her sister had missed work.
Akin called midmorning; he said he was sorry and began crying, according to a recounting of the conversation included in court documents.
“I am standing in front of the police department,” Akin allegedly said. “I stabbed your sister.”
Minutes later, Akin would walk into the Powell Police Department, eventually explaining to officers that he was there to turn himself in for the murder of his girlfriend, the 21-year-old Autumn Rose Rivera, and that they would find her body in the trunk of her car outside.
Akin was formally arrested at the police station by the Wyoming Division of Criminal Investigation on the afternoon of Nov. 27. He’ll soon be returned to the Denver area, where police obtained a warrant for his arrest.
The Office of the Coroner in Adams County, Colorado, officially identified Rivera as the deceased in a Monday news release. The coroner’s office said the cause and manner of Rivera’s death remains under investigation.
Police in Thornton, Colorado, say they’ve gathered evidence that Akin, 22, stabbed Rivera during an argument that became physical.
A rough outline of the alleged crime — including Akin’s conversations with Rivera’s sister — is contained in an affidavit of probable cause, included with a request to have Akin held in custody in connection with Rivera’s murder.
At a Friday morning appearance in Park County’s Circuit Court in Cody, Akin initially declined to sign a waiver of extradition. However, after visiting with a court-appointed attorney, Travis Smith of Cody, he signed the form later in the day, agreeing to be transferred to Adams County, Colorado, without a delay.
He remained in the Park County Detention Center on Monday afternoon, waiting to be picked up by Colorado authorities. Prosecutors in Adams County had not formally charged Akin with a crime as of Monday afternoon. The case “has not been presented to us yet,” said Sue Lindsay, a spokeswoman for the 17th Judicial District Attorney’s Office.
Thornton police — who will ulimately present their evidence to the prosecutor’s office — say they’re investigating Rivera’s killing as a possible first-degree murder case.
In the affidavit included in court records, Thornton Police Det. Robin Danni alleges that Akin not only admitted to killing Rivera in interviews with Powell police and the phone conservation with Rivera’s sister, but also in conversations with his mother and a family friend. The accounts of the crime that Akin allegedly gave to those people differed somewhat from person to person, according to the recollections shared with police and recounted in the affidavit.
For instance, he allegedly told police and his mother that he had blacked out while cutting fruit.
In a conversation with Powell Police Sgt. Chad Miner, “Akin said he had woken up on Sunday morning [Nov. 25] and found his girlfriend on the floor dead,” Det. Danni wrote. “[Akin] said he laid on the floor with his girlfriend all day trying to recall what had happened the night before because they had drank a lot of alcohol.”
Miner asked Akin if he was sure Rivera was dead and where she was, so police could check on her; Akin allegedly responded that his girlfriend was in the trunk of his car, parked in front of the police station.
Officers found Rivera’s body wrapped in a bedspread in the back of Akin’s Honda Civic.
In the couple’s Thornton, Colorado, apartment, police found bedding was missing “and there was a strong smell of cleaning solution,” Danni wrote. It was enough for Thornton police to conclude that the apartment was a crime scene.
Akin’s mother lives in Deaver and he reportedly traveled from Thornton to Deaver on Monday, Nov. 26, arriving around noon.
He did not sleep well that night and seemed “down” on the morning of Tuesday, Nov. 27, his mother told police.
When she asked her son what the problem was, Akin reportedly responded, “I killed her.”
According to Danni’s affidavit, Akin told his mother he couldn’t remember what had happened; Akin reportedly said he’d blacked out after Rivera yelled at him while he was cutting fruit.
Akin and his mother drove to the Powell police station later that morning.
Shortly before going inside, Akin allegedly called Rivera’s sister, Amber, and confessed. She hung up on Akin and contacted police in her home state of Texas.
Akin, meanwhile, then called a family friend, who would later tell police that Akin was crying and hysterical. He reportedly told the friend that Rivera had pushed him, he had pushed her and, according to the friend’s recollection, Akin either said he “flipped out” or “lost it” after that.
A friend and former roommate of Rivera’s and Akin’s, Kateyln Neuhold, said in an interview on the Denver TV station FOX31 that the couple “would have these really bad fights.”
She added to another channel, Denver 7, that “no one saw this coming at all. This was a complete shock.”
“It’s just hard to believe he would ever do something like that — especially to someone that he cared about so much,” Neuhold told Denver 7. She called Rivera “just sweet and caring.”
Amber Rivera described her sister as her very best friend.
“The pain and confusion and loss of my sweet angel is more than I will ever be able to put into words,” Amber wrote on Facebook. “My sister was the most beautiful, smartest, toughest, and bravest person I’ve ever known. She will be so very missed.”
Autumn Rivera had recently started a new job at a bank and studied exercise science at Harding University in Searcy, Arkansas, and at the Metropolitan State University of Denver, according to her Facebook page.
In a post on Instagram earlier this year, Akin indicated that he and Rivera had met in late 2017. They officially announced their relationship on Facebook in February.
Akin’s most recent post on Instagram, from Aug. 30, featured a photograph of him and Rivera.
“Excited for what the future has in store for us (:” he wrote.