A Mother’s Nightmare: How Two Brothers Became Killers and a Small Town Was Shattered

Introduction

On a quiet Sunday morning near Aztec, New Mexico, Tiffany Chaffen was simply a mother, tending to her sons Tyler and Eli in their remote family home. By sundown, she would be thrust into the worst day of her life—forced to confront the horrifying truth that her teenage boys were wanted for murder. This is the story of how a routine day collapsed into a brutal killing, a frantic manhunt, and the unraveling of a family, told through the eyes of law enforcement, witnesses, and a mother who never saw it coming.

The Calm Before the Storm

The Chaffen brothers’ Sunday began like any other—watching gun YouTubers, playing video games, and lounging in the living room. With them was Sierra Collins, a young woman with a troubled past. At one point, she turned to the brothers and asked a chilling question: “Would you kill for me?”

Her phone buzzed, and something snapped. Sierra told the brothers they were going for a ride—and to bring their guns.

Two hours later, in a quiet trailer park, four gunshots shattered the peace. Residents rushed to their windows and saw a man lying motionless in a puddle of blood as a car sped away. The victim was William Johnson, known locally as Bubba—a father of two daughters.

Within minutes, 911 calls flooded in. Officers rushed to the scene, uncertain if the shooter was still nearby. The following hours would become a harrowing manhunt, the likes of which the town had never witnessed.

The Crime Scene

Police arrived to find William Johnson face down in the grass, his body marked by four gunshot wounds. The scene was eerily calculated, resembling an execution rather than a chaotic shootout. There was no gun in sight, suggesting Johnson was unarmed.

A trail of footprints led officers to a nearby house. Inside, they found women’s clothing, drug paraphernalia, and family photos of a man resembling the victim. Neighbors confirmed the identity: William Johnson, 37, and mentioned Sierra, his ex-girlfriend, who had been living there and was often seen arguing with him.

As officers canvassed the area, a witness described seeing a white Chevy Blazer with gold trim speeding away after the shots. The search was on.

The First Leads

One officer encountered a driver who claimed to be Sierra’s friend and provided her full name and phone number. Sierra Collins, 23, had a record of drug offenses and a restraining order against William. She’d recently completed rehab, was trying to regain custody of her son, and hoped to become a teacher.

Detectives called Sierra, who seemed nervous but agreed to come to the station. The upcoming interview would blow the case wide open, with the Chaffen brothers on the run, sparking a multi-hour manhunt.

Sierra’s Interview: The Domino Falls

Sierra arrived at the station, visibly shaken. The detective asked about William’s phone, hoping she’d help unlock it. Instead, Sierra balked, worried there was something incriminating on the device. Her reluctance raised red flags.

Pressed further, Sierra finally broke down—though not out of grief, but fear of trouble. She admitted knowing who killed William but refused to say more inside the interrogation room. The detective took her outside for a walk, leaving his body camera behind, hoping she’d finally talk.

Outside, Sierra revealed that Tyler and Eli Chaffen—her friends from rehab—were the killers. She insisted she had no part in the murder, claiming the brothers were unstable and that Eli simply wanted to kill someone. But her version conveniently omitted the week-long plan she’d set in motion to get William killed, letting someone else take the blame.

Detectives confiscated Sierra’s phone, searching for evidence. Meanwhile, they discovered Tyler Chaffen was a convicted felon with a prior arrest for assaulting a peace officer. The Chaffen household contained several registered firearms. The brothers were now considered armed and extremely dangerous, prompting SWAT to join the manhunt.

The Manhunt

Across town, the Chaffen brothers were packing guns and preparing to flee. Convinced Sierra had betrayed them, SWAT teams moved to ambush the brothers at their parents’ home. The goal: apprehend the suspects without casualties.

SWAT surrounded the home, attempting to draw the brothers out. After several unsuccessful attempts, they breached the residence, finding half a dozen guns but no sign of Tyler or Eli.

Then, a white SUV matching the suspects’ description approached. Officers drew their guns, bracing for a shootout. The brothers were arrested without incident, an AR-15 rifle found in their car—a stark reminder of how deadly the confrontation could have been.

The Interrogation: Brothers at Odds

The brothers were placed together in a police vehicle equipped with a microphone, hoping to capture incriminating conversation. Tyler, the older brother, immediately took charge, instructing Eli not to cry or mention self-harm, and to stick to their story. The police separated the brothers for questioning.

Detective Decker, recently promoted to sergeant, was assigned to interview them. Eli, 19, insisted on having his mother present—an unusual request for an adult, but Decker complied. He then turned to Tyler, who played oblivious, claiming not to know why he was there.

Pressed, Tyler confessed to the shooting, attempting to frame it as self-defense. He said William approached their vehicle aggressively, that he hit William with a pistol, and that Eli shot William during a struggle. Tyler’s explanation implicated his brother, whether intentionally or not.

But the gunshot pattern on William’s body told a different story—one of execution, not self-defense. Tyler became emotional, expressing regret and blaming Sierra for manipulating them into the killing.

Sierra’s Role Unraveled

Detectives reviewed messages on Sierra’s phone and found evidence of her involvement. She had orchestrated the plan, sending text messages to William and leading the brothers to his home. When confronted, Sierra insisted she was innocent, that Eli simply wanted to kill someone. But her phone was filled with incriminating messages she couldn’t explain away.

Sierra was placed under arrest for murder, her breakdown at the end of the interview hinting at a much darker twist awaiting her.

Tiffany’s Worst Day

Detective Decker called Tiffany, asking her to come to the station. Shocked, she arrived within minutes. When told her sons were accused of murder, her reaction was strange—more confused than devastated.

Decker allowed Tiffany to be present during Eli’s questioning, hoping her presence would encourage him to open up. Eli stuck to the story he and Tyler concocted, pretending not to know William Johnson, though he admitted knowing Sierra.

Decker pressed Eli about his fascination with guns. Eli insisted he wasn’t aggressive, emphasizing his history of being bullied. Tiffany jumped in to defend him, describing her son as timid and gentle.

Finally, Decker confronted Eli with Tyler’s confession. Eli broke down and recounted the events—how he shot William to protect his brother, claiming self-defense. Tiffany struggled to listen as her son described committing murder, clinging to the hope that her boys had acted only to protect each other.

But Decker challenged that belief, pointing out inconsistencies and evidence of premeditation.

The Final Truth

After interviewing both brothers, Decker concluded that the Chaffens went to William’s house with guns, intending to confront him. Tyler maintained the self-defense story but became more adamant about Sierra’s role, claiming he was set up.

Tyler requested a second interview, hoping to shift the narrative and protect Eli. He admitted he didn’t have full control over the weapon, contradicting his earlier statements. Decker realized Tyler’s main concern was his brother, not himself.

“You and your brother murdered somebody, and you helped do that,” Decker told Tyler. “Your biggest fear right now is that you’ve made things pretty rough for your brother.”

Despite the brotherly bond, the evidence was overwhelming. Sierra had manipulated the brothers, but they had gone to William’s house on their own accord.

The Aftermath

Murder charges were filed against all three. Tiffany never stopped supporting her sons, staying in contact with both, hoping the truth would help them find a way out. Jail calls captured a glimpse of a mother caught between the children she’d raised and the reality of what they’d done.

In September 2024, while awaiting trial, Sierra suffered a severe medical emergency at the San Juan County Detention Center. She was transferred to the regional medical center but died shortly afterwards.

In July 2024, both Chaffen brothers entered plea agreements. Eli pleaded guilty to voluntary manslaughter, while Tyler pleaded no contest to second-degree murder and felon in possession of a firearm. Eli was sentenced to six years in prison, followed by two years of parole. Tyler received fifteen years, also followed by two years of parole.

Epilogue: A Family Shattered

Tiffany’s nightmare ended with both of her sons behind bars and Sierra dead. She continued to support Tyler and Eli, believing they were manipulated by Sierra and acted out of fear. The brothers, once ordinary teenagers, were now convicted killers, their lives—and their mother’s—forever changed.

Aztec, New Mexico, would remember the day a routine Sunday turned into tragedy. A mother’s love endured, but the bond between her sons became the thread that unraveled an entire family.