If Idaho mother Andrea Shaw goes to trial for the deaths of her twin toddlers, jurors will have to decide which is true: whether the 18-month-olds died of a mysterious illness possibly caused by vaccinations or whether their mother killed them.
Prosecutors, who plan to seek the death penalty for Shaw, say that suffocation "is the only conceivable explanation" for the deaths of her 18-month-old son Tyson and his twin sister Dallas in May 2025 in Payette, a small city in western Idaho near the state's border with Oregon. Police arrested Shaw on murder charges in June, more than a year after their deaths.
Shaw's defense attorney says that she would never have hurt the children, a county coroner found that the deaths were "undetermined," and that prosecutors
have no evidence proving murder. He says Tyson and Dallas, who were born three months premature, became sick after receiving flu shots and childhood vaccinations.
"All she's ever wanted to be is a mom and to be the best mom she could be," Shaw's attorney, Joe Filicetti, told USA TODAY. "She absolutely loved and adored the twins. ... I believe with every fiber of my being that she didn't do it."
In the year and a half since the twins' deaths, Shaw has become a cause célèbre for one of the nation's most controversial issues: vaccination skepticism. The anti-vaccination group Children's Health Defense, which was founded by Health Secretary Robert F. Kennedy Jr., has been defending Shaw on its YouTube page and even interviewed the young mother and her husband about three weeks after the twins' deaths.
During the tearful interview on CHD.TV, Shaw said that her children were "perfect happy little babies" before their vaccinations and that she believes the shots are responsible for their deaths.
"They had got their shots at the same time by two nurses at the same time, and they got sick − the same symptoms − the following morning," Shaw said in the interview, explaining why they may have died at the same time a week later. "They had a bond. ... It makes sense in my mind but I can see where it doesn't to people that don't know this side of the story."
Shaw's trial is set for Jan. 11 but Filicetti is fighting to stop it before it starts. He filed a motion to dismiss the whole case on Oct. 21, which came five days after prosecutors indicated their intention to seek the death penalty.
"This is a charging decision in search of facts, and they don't have those facts," Filicetti said. "There's no chance a jury is going to find this guilty beyond a reasonable doubt."
A hearing on the motion to dismiss the two first-degree murder charges against Shaw is before Judge Kiley Stuchlik of the 3rd Judicial District of Idaho. Stuchlik revoked Shaw's $2 million bond and ordered her jailed in July, saying that she could be a threat to her newborn baby, Keaton Hope, who Filicetti says was just 5 days old when Shaw was arrested in the deaths of Tyson and Dallas in June.
As Shaw waits to hear whether she'll face trial in January, USA TODAY is looking closer at the case, including its ties to the anti-vaccine movement and what else prosecutors have shared about what they believed happened to the Tyson and Dallas.
Prosecutors: Shaw showed 'utter disregard' for life
Prosecutors are being tight-lipped with what evidence they have, and some of the documents in the case are under a court seal.
Filicetti said that the county coroner listed the cause of death as undetermined and indicated it could be hypothermia, caused by too much heat. But Payette County Prosecutor Mike Duke said in court documents that the autopsy showed symptoms consistent with smothering and that "the only conceivable explanation" is that they were suffocated, according to a court filing obtained by USA TODAY.
"Over the course of their investigation, officers ruled out heat, carbon monoxide poisoning, any other known form of poisoning, and vaccines," Duke wrote in the filing.
Both children had pulmonary vascular congestion and Dallas had pulmonary edema, conditions that both "are consistent with being smothered," Duke wrote.
"This is the cause of death of the twins," he said in the filing. "It is also the only reasonable explanation for why both would die at the same time, on the same night, in the same room, in the same bed."
In their notice seeking the death penalty, prosecutors indicated that they would try to prove four aggravating factors, including that Shaw showed "utter disregard" for human life, that her actions were especially "heinous, atrocious, or cruel," and that she poses a threat to society, according to the notice.
When reached by USA TODAY, Duke said it's "important that people understand that Ms. Shaw has the right to a presumption of innocence, and it is my duty to convince a jury beyond a reasonable doubt of her guilt."
He added: "I plan to fulfill that responsibility at trial."
Did Andrea Shaw blame vaccines for babies' deaths?
Filicetti told USA TODAY that the defense's position is that "there was overload," citing Dallas' and Tyson's premature births and the fact that they got the flu and vaccination shots all at once.
He said that Shaw begged a pediatric nurse not to give her babies the flu shot while they were getting vaccinated on April 23, 2025, because her husband and mother-in-law both had a negative reaction.
"The pediatric nurse practically said, 'No, you don't know what you're talking about,'" Filicetti said. "Immediately the kids started having problems. The next morning they had blue lips, hands and feet."
He said Shaw took them to the emergency room, where they were given Pedialyte popsicles and sent home. He said the babies were ill the rest of the week leading up to the night of April 30, 2025, when he said that Shaw decided to take a break and go out with friends, leaving the twins home with their dad, Nathaniel Shaw.
The twins appeared to be sleeping when she left at 11 p.m. and again when she got home at 2 a.m., Filicetti said. He said she visually checked on them again at 8 a.m. and assumed they were still sleeping. When she checked on them again at 11 a.m. on May 1, he said rigor mortis had set in but that she called 911 and tried to perform CPR.
Filicetti described Shaw as vax-hesitant and said that no one knows for sure what caused the twins' deaths, including the coroner. "We don’t know what happened, but the fact that we don’t know doesn’t mean the prosecution does," he said.
Children's Health Defense has been defending Shaw on its YouTube page, which has just over 3,200 followers. Health Secretary Robert F. Kennedy Jr, who founded the group, left it in 2024 after President Donald Trump nominated him to lead the Department of Health and Human Services.
"We have ample photos of Andrea Shaw as an intensely loving mother who was caring for two premature toddlers," Mary Holland, CEO of Children’s Health Defense, said in a recent video. "There's no basis that we are aware of that would suggest she is of any threat to society, nor do we think that there's any basis to assert that she murdered her children. ... We believe strongly that she is not guilty."
Shaw joined a lawsuit filed last year by Children's Health Defense against the American Academy of Pediatrics. The ongoing lawsuit accuses the American Academy of Pediatrics of lying about how safe vaccinations are.
During her interview with Children's Health Defense in May 2025, Shaw said she had previously not been against vaccinations and that Tyson and Dallas had gotten some following their births when they were in a Neonatal Intensive Care Unit (NICU).
"I think we said no to a few vaccines just because I would do my research before I would give consent," she said, later adding that she allowed the babies to get all the recommended vaccines when they were 18 months but now regrets it. "I wish I was anti-vaccine now."
She recalled how police immediately treated her as a suspect.
"They said that it it wasn't medical, and that they they figured asphyxiation, and that I had supposedly had a postpartum overwhelming blackout and done it to my children," she said. "It made me feel crazy because I was telling them my truth and it was getting into my head that I had done it and I know I hadn't."
Her husband Nathaniel told CHD.TV that his wife never would have killed their babies and that detectives attempted to pit him and his wife against each other in order to arrest one of them.
"They constantly were trying to pin me and Andrea against each other, trying to get us to say, 'Well, I think she did it,' or 'I think he did it,'" he said. "They were just very adamant that we had done it. ... I had looked at the detectives, and I told them that I was extremely pissed off at the fact that they thought my wife had the capacity to do so, as she was such a loving and caring mother."
Experts weigh in on biggest challenges facing prosecution, defense
Neama Rahmani, a former federal prosecutor who is closely watching Shaw's case, said one of the biggest challenges facing defense attorneys is the fact that Tyson and Dallas died at about the same time.
"It’s a little bit of a red herring," he told USA TODAY. "What are the chances of two kids dying at the exact same time? No question, that makes it significantly more challenging."
Rahmani expressed surprise that prosecutors filed a notice seeking the death penalty. In Idaho, the firing squad is the primary method of execution.
"I understand why someone who kills their two children should be executed but it's pretty aggressive in a case like this when there are potential medical causation issues," he said. But, he added that prosecutors may have done it for some leverage when it comes to a potential plea negotiation down the road.
Though prosecutors have shared little of the evidence they're going to put before jurors, Rahmani said he's certain that they have found multiple experts who will testify that the toddlers most likely were suffocated.
"They have something that we don’t know because you don’t file a case like this unless you know you can get it across the finish line," he said. "It's going to come down to a battle of the experts. It's going to be an interesting case."
Dr. Michael Baden, a forensic pathologist who has worked on high-profile cases involving the likes of O.J. Simpson and Jeffrey Epstein, called Shaw's case "rare as hell," pointing to the simultaneous deaths of the twins.
Complicating the case, he said, is that suffocation doesn't normally leave a mark on a body. Plus, he said congestion and edema can be present in any number of natural deaths and don't necessarily mean suffocation.
In other words, such cases are difficult to detect, Baden said. He pointed to Marybeth Roe Tinning, a Schenectady, New York, woman sentenced to 20 years in prison for using a pillow to suffocate her 4-month-old daughter Tami Lynn in 1985. Before that, Tinning's eight other children died under mysterious circumstances between 1971 and 1981, according to archived news reports.
In Shaw's case, Baden said the fact that the county coroner listed the cause of death as "undetermined" may come back to haunt the prosecution.
"If it's undetermined normally the perpetrator wins," he said.
Whatever happens, the case stands to garner nationwide attention the likes of which we haven't seen since the Lindsay Clancy trial.
"A case will get a lot of attention anytime a mother kills her kids," Rahmani said. "And there's a very small but vocal community supporting her and blaming the vaccinations so i think it's going to get a lot of attention once it gets closer to trial."
The next big hearing in the case is set for Dec. 2, when the judge is expected to consider the defense's motion to dismiss the case. The trial is set for Jan. 11
Amanda Lee Myers is a senior crime and courts reporter who covers the death penalty, cold cases and breaking news for USA TODAY. Follow her on X at @amandaleeusat.
This article originally appeared on USA TODAY: Idaho mom accused of killing toddler twins: Was it vaccination or murder?
