FAIRFAX, Va. – A Virginia man faces trial on Monday over allegations of plotting a complex double-murder to implicate another in his wife’s stabbing. The case involves his relationship with a Brazilian au pair.

Brendan Banfield stands accused of aggravated murder in the February 2023 deaths of his wife, Christine Banfield, and Joseph Ryan, which occurred at the couple’s northern Virginia residence. Banfield has entered a plea of not guilty.

On the day of the tragic event, court documents indicate that Banfield and the family’s au pair, Juliana Peres Magalhães, were present at the home alongside Christine and Ryan. According to authorities, Banfield and Magalhães initially claimed they witnessed Ryan, an unfamiliar intruder, attacking Christine in the master bedroom. They reported shooting him in what they described as self-defense.

However, prosecutors contend otherwise, suggesting that Banfield and Magalhães orchestrated Ryan’s visit to set up a scene where they appeared to defend themselves against an assailant. The two are said to have begun a romantic relationship the year preceding the murders, according to officials.

In 2023 and 2024, both Banfield and Magalhães were arrested and charged with murder. By 2024, Magalhães had agreed to a plea deal, admitting to a lesser manslaughter charge and corroborating key elements of the prosecution’s narrative.

In that statement, Magalhães said she and Brendan Banfield created an account in his wife’s name on a social media platform for people interested in sexual fetishes. There, Ryan connected with the account in Christine Banfield’s name, and the users made plans to meet on the morning of Feb. 24, 2023, for a sexual encounter that would involve a knife, authorities said based on the statement from Magalhães.

Prosecutor Eric Clingan said last year that the au pair’s statement helped the state solidify its theory ahead of trial.

“With 12 different homicide detectives, there were 24 different theories,” Clingan said. “Now, one theory.”

Not all officials investigating the case have believed Banfield and Magalhães catfished Ryan.

Brendan Miller, a former digital forensic examiner with the Fairfax County Police Department, testified last year that he analyzed dozens of devices and concluded Christine Banfield had connected with Ryan herself through the social networking platform.

An evidence analysis team at the University of Alabama peer-reviewed and affirmed Miller’s digital forensic findings, according to evidence submitted to the court.

Miller was transferred out of the department’s digital forensics unit in late 2024, though a former Fairfax County commander testified the reassignment was not punitive or disciplinary.

John Carroll, Banfield’s attorney, argued that Millers’ transfer was directly tethered to the case. He also said in court that Fairfax County police reassigned the case’s lead detective after that man had pushed back on the top brass’ catfishing theory.

“It is a theory in search of facts rather than a series of facts supporting a theory,” Carroll said.

Banfield, whose daughter was at the house on the morning of the killings, is also charged with child abuse and felony child cruelty in connection with the case. He will also face those charges during the aggravated murder trial.