Nanny Pleads Guilty to Manslaughter in Double Homicide, Agrees to Cooperate Against Ex-Lover

A Brazilian au pair who was charged in connection with the deaths of her ex-lover’s wife and another man has pleaded guilty to manslaughter to one of the slayings.

The plea deal between Fairfax County, Va., prosecutors and Juliana Peres Magalhaes, 24, was the latest development in the bizarre double homicide case.

Fairfax County Commonwealth’s Attorney Steve Descano said Peres Magalhaes’ plea agreement on Tuesday, Oct. 29, in the shooting of 39-year-old Joseph Ryan, marked a "significant step forward in this case, and it is an important development in our pursuit of justice for the victims and their families."

Peres Magalhaes' ex-lover Brendan Banfield was indicted in September by a Fairfax County grand jury on four charges of aggravated murder and one charge of use of a firearm in the commission of a felony in connection with the deaths of Ryan and Banfield's 37-year-old wife, Christine Banfield.  

Christine Banfield was discovered mortally wounded after being stabbed in her Herndon, Va., home on February 23, 2023. She died later in the hospital. Ryan was found dead nearby — with gunshot wounds to the head and chest. 

Prosecutors allege Peres Magalhaes and Brendan, a former agent for the criminal division of the Internal Revenue Service, began an affair in Aug. 2022, after she moved into the Herndon, Va. home Brendan shared with Christine, a pediatric intensive care nurse, and their then 4-year-old daughter. 

According to remarks made by Deputy Commonwealth’s Attorney Eric Clingan in County Circuit Court in Fairfax at the Oct. 29 plea hearing, Brendan soon after “expressed his desire to be rid of his wife.” 

The month before the murders, Brendan allegedly created a profile on the bondage website Fetlife.com and began communicating with Ryan, a mixed martial arts enthusiast who liked live action role-playing. 

Brendan then allegedly directed Peres Magalhaes to call Ryan, pretending to be Christine, using an encrypted messaging application called Telegram, to confirm details “that both parties were willing participants.”

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Clingan said Brendan “lured” Ryan to the home on the morning of Feb. 24, 2023, alleging that “Ryan likely believed that he was meeting Christine Banfield to have a consensual sexual encounter involving restraints used on her, her clothing being cut off with a knife he brought, and other violent sexual role play.”

Brendan allegedly gave Peres Magalhaes a gun he bought a month earlier and told her to call Christine’s phone when Ryan entered the home and then to call Brendan “saying there was a strange man at the house, and she was scared,” Clingan said.

The call to Christine’s phone went straight to voicemail because Brendan allegedly turned her phone off and put it in a kitchen drawer before he left home that morning. 

Brendan received Peres Magalhaes’ call while he was at a nearby McDonald’s “waiting so that he could return quickly,” Clingan said.

Prosecutors allege Brendan then drove home, where he shot Ryan in the head and stabbed his wife.

Peres Magalhaes “saw Joseph Ryan moving, and shot him,” according to Clingan. 

The duo then “reported the offense as if Joseph Ryan was an intruder who stabbed Christine Banfield,” said Clingan.

After serving warrants on the Banfield home in October 2023, investigators found photos of Brendan and Peres Magalhaes “in loving poses” arranged throughout the bedroom along with the au pair’s lingerie. That same month, Peres Magalhaes was charged with second-degree murder and use of a firearm in commission of a felony in the death of Ryan. She was not charged in connectoin with Christine's death.

After two years in custody and just days before she was scheduled to go to trial, on Oct. 25, the former au pair gave a “detailed account” of the killings that “corroborated evidence discovered” by Fairfax County Police, Clingan said.

She is facing up to 10 years in prison. However, The New York Times reported that prosecutors agreed to recommend that Peres Magalhaes be released from custody with credit for time served after Brendan's trial provided she continues to cooperate with authorities.

A sentencing date has been set for March 21, 2025. Brendan is scheduled to go to trial on Feb. 3, 2025.