The state says an Oregon mother researched possible methods before choosing a vehicle exhaust setup intended to make the family fall asleep.
SALEM, Ore. — Prosecutors say an Oregon mother spent about a week researching how to kill herself and her three young sons before placing them in a car fitted to carry engine exhaust into the passenger area.
The allegation of advance planning shaped the state’s first public account of the case against Chardonnay Marie Benavidez, 32, of Keizer. At her Marion County Circuit Court arraignment, a prosecutor said Benavidez had considered several options before deciding on carbon monoxide. The prosecutor said she viewed it as a way for the family to fall asleep together. Authorities allege that she put the plan into action June 6 with twin 2-year-old boys and their 4-year-old brother. All three survived after Benavidez removed them from the vehicle and called 911.
The state’s account begins before the family entered the garage. Prosecutors said Benavidez researched carbon monoxide poisoning for roughly a week, although officials have not disclosed where she conducted the research or which records investigators recovered. It remains unknown whether police seized a phone, computer, written notes or internet account data. The prosecutor also referred to “multiple options” that Benavidez allegedly considered, but did not publicly describe each method. Those details could become important because they may help the state argue that the events were deliberate rather than accidental or impulsive. The available reports do not say whether investigators found purchases, messages or communications made during that week. They also do not identify anyone who may have known about the alleged plan before June 6.
Prosecutors allege that Benavidez then turned the family’s vehicle into the means of carrying out the plan. Police said a tube or similar makeshift device connected the exhaust pipe to the car’s interior while the vehicle sat in an attached garage at the family’s home on Holly Court Northeast. The state alleges that Benavidez invited the children into the car by saying they would have a “sleepover.” Their ages made them dependent on the adult caring for them and unable to understand the danger described by investigators. Authorities estimate that Benavidez and the boys remained in the running vehicle for about 20 minutes. Police have not said whether the windows were open or closed, where each child was seated or whether the doors were locked.
The alleged plan did not end as prosecutors say Benavidez first intended. Authorities said the children began showing signs of carbon monoxide exposure and moved in and out of consciousness. Benavidez removed them from the vehicle and took them into the living room. At about 8:20 p.m., she called 911 and reported that she had tried to kill them and herself, according to police. The timing creates two distinct sets of facts for the court to consider. One concerns the alleged preparation and exposure inside the car. The other concerns her decision to stop, move the children and summon help. Oregon law and the evidence presented later will determine what effect, if any, that reversal has on the charges, possible defenses or an eventual sentence.
Police arrived to find Benavidez and all three boys in the house. They could not safely enter the garage because fumes remained heavy enough to burn officers’ eyes and make breathing difficult. Firefighters used self-contained breathing equipment to enter, open the space and vent the exhaust. Investigators then examined the car and recovered the device they say carried fumes into the cabin. The physical scene may provide evidence about how the apparatus worked, whether it was deliberately secured and how long the engine operated. Police have not released carbon monoxide readings from the garage or vehicle. They also have not said whether the engine was still running when emergency crews arrived or whether Benavidez turned it off before making the call.
A gun found in the vehicle added another element to the prosecution’s description of intent. According to the state, Benavidez told investigators that she planned to shoot herself if the exhaust killed the boys but failed to kill her. Officials have not identified the gun’s owner, model or condition. They have not said whether it was loaded, where inside the vehicle it was found or whether it had been moved during the emergency response. No one was shot, and authorities have not reported a firearm charge. Even so, prosecutors may use the weapon and the reported statement about it to support their argument that Benavidez expected the children to die and had planned for a possible outcome in which she remained alive.
The children and their mother were taken to Salem Hospital for treatment. Public reports have not described the tests performed or released blood measurements showing the degree of exposure. The boys were medically cleared June 7 and released to their father with assistance from the Oregon Department of Human Services. Benavidez remained at the hospital under a physician’s hold and received a psychiatric evaluation. After medical workers cleared her the same day, police arrested her and took her to the Marion County Jail. The psychiatric hold was a medical measure during the emergency and does not establish whether she can be held legally responsible for the charged conduct. Criminal responsibility, competency and any mental-state defense involve separate legal standards and court procedures.
Benavidez faces three attempted murder counts because prosecutors allege that each child was an intended victim of the same plan. She also has been reported as facing three first-degree assault counts. The attempted murder case is likely to focus heavily on intent. Prosecutors may point to the alleged research, the sleepover statement, the constructed exhaust system, the duration inside the vehicle, the children’s symptoms and the gun. Defense lawyers could examine the reliability and context of every statement, including what Benavidez said while suffering from possible carbon monoxide exposure or undergoing a mental health crisis. They may also seek medical records, dispatch audio, police video, search warrants and forensic reports before deciding whether to challenge the charges or negotiate a resolution.
The initial courtroom presentation came from the prosecution, not from witnesses under cross-examination. No jury has heard the evidence, and a charging allegation is not a finding of guilt. Investigators must preserve the physical device, document the vehicle and establish a clear chain of custody for items removed from the garage. They may seek digital evidence supporting the alleged research and interview medical personnel who treated the family. The children’s ages make direct interviews sensitive, and officials have not said whether specialists spoke with them. The statement that Benavidez described the outing as a sleepover may have come from her own account, from a child or from another source. Public reporting has not clarified that point.
Keizer police said they were unaware of previous reports indicating that Benavidez posed a danger to the boys. The children’s father, Antonio Benavidez, also described her as having been a devoted mother before the incident. His reaction does not resolve the state’s case, but it adds context to investigators’ statement that the alleged danger was not part of a known pattern involving the children. Authorities have not released a detailed family history or identified a recent event that might explain the timing. The prosecutor’s account centered instead on Benavidez’s reported research and her selection of a method. A motive beyond the alleged murder-suicide plan remains publicly unexplained.
A judge ordered Benavidez held without bail after her arrest. An early report listed June 17 as her next court date, but no later verified account reviewed for this article established the result of that appearance. The case may proceed through additional charging decisions, evidence exchanges, motions and hearings before any trial. A competency examination could be requested if an attorney or judge raises a legal question about her ability to understand the case and assist in her defense. That process would differ from determining her mental condition on June 6. No public filing reviewed here established that either issue had formally been raised.
The prosecution’s opening theory presents the alleged poisoning as the final act of a plan developed over several days. The defense has not yet offered a public account testing that theory. Until court records establish otherwise, Benavidez remains presumed innocent, and the state must prove the purpose and meaning of each piece of evidence it has described.
Author note: Last updated July 11, 2026.