Northern Virginia

Au pair takes guilty plea in Herndon killings, will cooperate with prosecutors

Prosecutors say Brendan Banfield and his au pair, Juliana Peres Magalhaes, were having an affair for months before his wife and a stranger were slain in their Northern Virginia home

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An au pair accused in a double homicide in Northern Virginia pleaded guilty Tuesday and agreed to cooperate with prosecutors against her alleged accomplice in the crime.

Juliana Peres Magalhaes and Brendan Banfield, the father of the family for whom she worked, are accused of working together to kill Banfield's wife, Christine Banfield, and a stranger, Joseph Ryan, inside the married couple's Herndon home in February 2023.

In court Tuesday, Peres Magalhaes told prosecutors she and Brendan Banfield used a fetish website to lure Ryan to the house.

Prosecutors said Ryan believed he was going there to meet Christine Banfield, for a consensual sexual encounter in which he would tie her down and use a knife to cut off her clothes. Christine Banfield had no idea of the plot, prosecutors said.

Ryan showed up to the house and began carrying out what he thought was the agreed upon plan, holding Christine down at knifepoint, according to prosecutors.

Peres Magalhaes told prosecutors she and Brendan Banfield then burst into the bedroom with guns, pretending to be surprised as if they hadn’t set the whole thing up.

According to the au pair, Brendan Banfield called out “police” because he worked as a federal agent for the Internal Revenue Service. Then, prosecutors say Brendan Banfield shot Joseph Ryan using his service weapon.

Banfield then allegedly stabbed and killed his wife.

Peres Magalhaes said she also shot Ryan because he was still moving. He died at the home.

Peres Magalhaes was arrested last October and charged with second-degree murder in the shooting death of Ryan.

A judge accepted the terms of Peres Magalhaes' plea deal Tuesday, allowing her to plead guilty to a lesser charge of manslaughter in Ryan's killing in exchange for her cooperation in the prosecution of Brendan Banfield.

Search warrant documents reveal new details about the jail conversations between Juliana Peres Magalhaes and Brendan Banfield. News4's Julie Carey reports.

"Today’s agreement marks a significant step forward in this case, and it is an important development in our pursuit of justice for the victims and their families,” Fairfax County Commonwealth's Attorney Steve Descano said. “Much of the information that led to this agreement cannot be made public at this time, due to the upcoming criminal trial against the other defendant in this matter."

Peres Magalhaes told prosecutors she didn’t want to go through with the murder plot, but Brendan Banfield allegedly told her it was too late to back out.

Peres Magalhaes faces up to 10 years in prison for the manslaughter charge.

The commonwealth's attorney plans to recommend Peres Magalhaes' sentence be capped at time served when she is sentenced — meaning she could stay in jail long enough for his trial, then would be released.

Prosecutors asked the judge to wait to sentence her until after Banfield’s trial, to ensure she continues to cooperate.

Banfield's trial date was set for Feb. 3, 2025. Peres Magalhaes' sentencing was scheduled for March 21, 2025.

Lawyers for Juliana Peres Magalhaes wanted some of her statements to Fairfax County police thrown out News4's Juliana Valencia reports.

A fetish site used as a lure?

A search of a computer in the Banfields' home led detectives to a fetish sex website, prosecutors said. The site catered to sexual fantasies involving kinks, BDSM and more.

Prosecutors said Brendan Banfield and the au pair concocted a plan to use the sex fetish website to lure Ryan to the home.

Detectives found a profile for Christine and communications between her profile and Ryan. But authorities said something didn't add up.

They said the way Christine talked to Ryan in their messages was very different than how friends and family described her. Police believe someone else was communicating with Ryan while pretending to be Christine and scheduled a meetup at the family's home for that day.

Nearly eight months after the killings, Fairfax County authorities arrested Peres Magalhaes and charged her with second-degree murder in Ryan's death.

Brendan Banfield was indicted in the murders of his wife and Ryan in September, nearly a year after Peres Magalhaes was arrested and more than a year-and-a-half after the killings.

Photos previously presented by the prosecution show Brendan Banfield with Peres Magalhaes in New York and at a concert venue. The two were involved in an affair for months before the killings, prosecutors said.

Other photos show Peres Magalhaes at a Virginia gun range. Attorneys also presented visitor logs of Banfield and Peres Magalhaes at the gun range.

While arguing that the couple had plans to flee the country, the prosecution showed photos of a new Brazilian passport for the au pair. Attorneys said Banfield drove Peres Magalhaes to the Brazilian consulate to apply for a new passport.

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