The Banfield home sits at the end of a quiet cul-de-sac — a two-story, Georgian brick revival much like its neighbors in an affluent northern Virginia community.
On a winter morning in February 2023, the scene inside was nightmarish.
A new “20/20” episode, “The Au Pair, The Affair and Murder” airing Friday, Feb. 20, at 9 p.m. ET on ABC and streaming the next day on Disney+ and Hulu, examines the case.
You can also get more behind-the-scenes of each week’s episode by listening to “20/20: The After Show” weekly series right on your 20/20 podcast feed on Mondays, hosted by “20/20” co-anchor Deborah Roberts.
When officers responded to a 911 call just after 8 a.m. that day, they found Christine Banfield, a 37-year-old pediatric nurse, bleeding out on the floor of her bedroom with seven stab wounds to her neck. A man, later identified as 39-year-old Joseph Ryan, lay fatally shot with gunshot wounds to the head and chest.
“The blood soaked through the carpet, through the foam pad, and then onto the subfloor,” Fairfax County homicide detective Terry Leach said, describing the scene at the Banfield home.
The homeowner, IRS agent Brendan Banfield, said on a 911 call that he came home to find Ryan — whom he did not know — stabbing his wife, Christine. Banfield said he used his government-issued firearm to shoot Ryan before rendering aid to his dying wife.
The Banfield family is pictured here in this undated photo.
Fairfax County Circuit Court
Also at the scene was the family’s 22-year-old Brazilian au pair, Juliana Peres Magalhães, who told police that she too shot Ryan — while the family’s 4-year-old child was left in the basement.
Ryan drove to the Fairfax County home on Feb. 24, 2023, to engage in what he believed was a consensual rape fantasy with Christine Banfield after finding a woman he thought was her on a sexual fetish website called FetLife, according to investigators.
Authorities wondered if the profile — under the name “Annastasia9” and showing a single photo of the married mother in a one-piece bathing suit — was actually created by Christine.
“When we start looking into a lot of the details of what’s going on in the digital evidence and the other evidence we’re finding outside of the digital evidence, a picture starts to develop of things that made investigators very suspicious,” Thomas Gadell, a Fairfax County Police homicide detective, told “20/20.”
“We found things in the messages where sentences were oddly phrased, like ‘How has been your experience on this site?’ which in and of itself could be a typo, but it could be a sign of somebody typing who maybe English isn’t their first language,” he said.
The question of what exactly happened inside the Banfield home plagued investigators for months.
It wasn’t until October 2024 that police served a second search warrant and found that Magalhães had moved into the primary bedroom. All photos of Christine had been removed from the home and instead a framed picture of Banfield and Magalhães sat on the nightstand.
A framed photo of Juliana Peres Magalhaes and Brendan Banfield appeared on a nightstand in the primary bedroom, according to investigators.
Fairfax County Circuit Court
“When we looked around the rest of the room inside the closet, throughout the room, we found Juliana’s clothing, Juliana’s lingerie,” Gadell told “20/20.” “Juliana had effectively replaced Christine.”
In October 2024, police arrested Magalhães, charging her with the second-degree murder of Joseph Ryan. By her initial account to police, she had fired the second and fatal shot.
Joseph Ryan’s mother, Deirdre Fisher also told “20/20” that she and her son had a close relationship. According to Fisher, Ryan told her that he engaged in rough sex and role play — although he always emphasized the importance of consent in these encounters.
“I knew Joe was very gentle as a person and concerned about the welfare of his romantic and sexual partners,” Fisher said.
Prosecutors anticipated Magalhães might flip on Banfield once in jail. Police said it took a year for Magalhães to confess, just after police arrested Banfield and charged him with aggravated murder, felony child cruelty and felony child abuse.
“There had been a lot of discussion about how we could get her to turn,” prosecutor Jenna Sands told “20/20.”
Body camera footage captured Juliana Peres Magalhaes speaking with officers outside the Banfield home after the fatal shooting.
Fairfax County Circuit Court
Magalhães pleaded guilty to a lesser charge of manslaughter and a sentencing recommendation from prosecutors of time served in exchange for her cooperation. This cooperation involved her testifying against Banfield should his case go to trial.
In January, the Commonwealth of Virginia launched a three-week-long trial against Banfield. Prosecutors began with nearly nine hours of testimony from Magalhães where she said that Banfield had concocted a plot to pose as Christine on FetLife to lure an unsuspecting man to the house.
Banfield took the stand in his own defense. While insisting that he loved his wife and that there was no plot to harm her, Banfield also recounted details from his multiple extramarital affairs, including his affair with Magalhães.
In an exclusive interview with “20/20,” one woman came forward to share details about her year-long affair with Banfield while he was married to Christine.
Body camera footage showed Brendan Banfield speaking with medical staff at the hospital after the shooting.
Fairfax County Circuit Court
The woman, who spoke to “20/20” on condition of anonymity, said she met Banfield in 2013 on a “sugar baby” website. After seven meetings, a relationship formed and the two would even meet in the Banfield home while Christine was away, she said.
“He would do these very detailed cleanings after I [would] leave because I have different colored hair from his wife,” the woman said. “He called it ‘CSI sweep,’ which was really stupid. But it was just like, I think he almost liked it. It was almost like a game to him. It was kind of like there’s a thrill, I think, to doing forbidden things.”
At one point, according to the woman, Banfield said things would be easier if his wife was out of the picture. She said that, at the time, she didn’t think much about it.
The jury deliberated for just over eight and a half hours before delivering their verdict, finding Banfield guilty on all counts on Feb. 2.
“I’ve seen a lot of different cases, different homicide cases, and I’ve never seen anything that was this planned, this premeditated, this calculated,” Gadell — the Fairfax County detective — told “20/20.”
Christine’s family wept in the front row of the courtroom gallery as the verdict was read.
In the wake of the verdict, her family released a statement to ABC News, in which they remembered Christine as an “honest, faithful, caring, compassionate, helpful person who was dedicated to her family, friends, and patients.”
“We are committed to ensuring that Christine will always be remembered as the beautiful person she was to everyone that loved her,” they wrote.
On Friday, Feb. 13, Magalhães was sentenced to 10 years in prison. Brendan is set to be sentenced on May 8. He faces a maximum sentence of life in prison without parole, as the death penalty was abolished in the state of Virginia in 2021.
For Lucille Priolo, there is no closure after the loss of her childhood best friend, Christine, whom she described as an “angel on earth.” But Priolo is determined to honor her friend, especially for the Banfields’ young daughter.
“I want to keep her memory alive just by talking about her, telling her stories and sharing who she was and remembering her laugh,” Priolo said. “That’s one of my favorite sounds. And sometimes I could look at a picture and I hear it because it was a pretty great laugh.”