WARNING: GRAPHIC CONTENT

The trial of Brendan Banfield, a former IRS special agent, began in Virginia on Tuesday, revealing shocking details as his alleged mistress took the stand. Banfield faces charges for orchestrating a brutal double murder intended to conceal his affair with the family’s au pair.

Banfield stands accused of the aggravated murder of his wife, Christine Banfield, and Joseph Ryan, which took place in February 2023 at their residence in Herndon, Virginia, a prosperous suburb near Washington, D.C.

The prosecution claims that Banfield spent an entire month posing as his wife on a fetish website. This deception was part of a scheme to lure Ryan to their home, where the double homicide was executed to keep his affair with the family’s 22-year-old Brazilian au pair, Juliana Peres Magalhães, a secret.

Prosecutor Jenna Sands, in her opening remarks, emphasized, “These two victims had no connection to one another except through the meticulous plotting and scheming of Brendan Banfield,” highlighting the connection between Ryan and Christine Banfield.

Brendan Banfield, charged with aggravated murder in the 2023 killings of Christine Banfield and Joseph Ryan, appears in court during opening statements on Tuesday, Jan. 13, 2026 in Fairfax, Va.   (Court TV via AP, Pool)

However, at the time of the alleged murders, Magalhães told investigators she and Banfield discovered Ryan stabbing Christine inside the home and both opened fire to stop the intruder. 

Defense attorney John Carroll insisted in his opening statement that Magalhães was arrested in October 2023 in an effort to pit her against Banfield during his trial. 

“The whole reason she was arrested was to flip her against my client,” Carroll said. 

Magalhães pleaded guilty to manslaughter in October 2024 and will be sentenced after Banfield’s trial. 

Juliana Peres Magalhães testifies during the trial of Brendan Banfield, charged with aggravated murder in the 2023 killings of Christine Banfield and Joseph Ryan, on Tuesday, Jan. 13, 2026 in Fairfax, Va.   (Court TV via AP, Pool)

In explosive testimony, Magalhães took the stand to detail how her relationship with Banfield went from professional to sexual. 

“We barely spoke,” Magalhães said. “My relationship was mostly with Christine and [the couple’s child].” 

Magalhães testified that the pair became intimate in August 2022, and how she first became aware of Banfield’s alleged plan to kill his wife while the pair were on a trip to New York with Banfield’s young child just two months later, with Banfield declining to file for divorce instead. 

“He mentioned his plan to get rid of [Christine],” Magalhães told the prosecution. “Initially, he didn’t know what he would do. He just mentioned that he would think about it [and] let me know when he thought about it.” 

A framed photo of Brendan Banfield and Juliana Magalhães and the mistress’s lingerie were found in the room where the double homicide occurred, according to prosecutors. (Fairfax County Commonwealth Attorney’s Office)

Magalhães explained on the stand that Banfield used his wife’s email and photograph to create an account on a fetish website under a fake name, while also conspiring to create an alibi in the event of a murder investigation. 

“He knew that we needed to have some alibis,” Magalhães testified. “He knew that he needed to change his routine a few weeks prior. So it wouldn’t be odd that he wasn’t, you know, just at McDonald’s on that day, specifically.” 

Prosecutors allege that Banfield and Magalhães propositioned men on the fetish website to enter the family’s home under the guise of a consensual sexual encounter, ultimately deciding on Ryan as their victim. 

“He made Brendan feel confident enough that he would be the person to play the role, which means being aggressive and holding her down and coming over to the house and bringing stuff and all that,” Magalhães said. 

Juliana Peres Magalhães is seen in new police bodycam video calling Brendan Banfield her “husband.” (Fairfax County Police Department via AP)

“Brendan created the narrative that Christine desperately wanted to be raped,” Sands explained in her opening statement. “Posing as Christine, he told Joe what to do: Come to the home in Reston. The door will be unlocked. Christine will be asleep in bed. Come straight upstairs, cut off her clothing, tie her, rape her. Simple and fun.” 

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Before Ryan arrived at the home, Banfield went to a nearby McDonald’s and awaited Magalhães’ call regarding an intruder at the home, the au pair testified. 

“After calling Christine, I called Brendan, and then he picked up the phone and I was telling him, ‘Stay away, there’s somebody strange and come to the house, I’m scared,’” Magalhães said. “He told me to stay there. He will be coming home, and he will try to call Christine.” 

Christine Banfield was stabbed to death in the bedroom of her Fairfax County, Virginia, home. (Facebook)

As the encounter unfolded, Banfield and the au pair put his young child in the basement with her iPad before entering the Banfields’ bedroom, where Banfield shot Ryan with his service weapon and stabbed his wife while Magalhães held a firearm he had purchased a month before the alleged killing, according to prosecutors. 

“When I got to the bedroom, Brendan yelled, ‘Police officer,’ and Christine’s first reaction – it was the first time I heard her say anything at that point – and she yelled back at Brendan, saying, ‘Brendan, he has a knife,’ and that’s when Brendan first shot Joe,” Magalhães said. 

Brendan Banfield and Juliana Magalhães, left, were charged in the killing of Christine Banfield, right. (Fairfax County PD, Instagram, and FOX 5 DC)

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Magalhães then testified, in graphic detail, how Banfield climbed on top of his wife and stabbed her in the neck while she covered her eyes and ears on the other side of the bed.  

“I had put my hands on the carpet and as soon as I felt blood, I just removed my hands from the carpet,” Magalhães said, adding that blood also soaked into her shoes and socks.

Banfield then allegedly staged the crime scene to appear as though it was a home invasion, with Magalhães then calling 911 to tell authorities Ryan was an intruder who had stabbed Christine, Sands added. 

Banfield’s attorney did not respond to Fox News Digital’s request for comment. 

If convicted, Banfield would face the possibility of life in prison. The trial is expected to last four weeks. Court sessions will begin at 10 a.m. each day and run Monday through Thursday, according to court administrators.