Affluent Virginia suburb rocked by love triangle murders as prosecutors highlight key evidence

Virginia prosecutors are pointing to blood-spatter analysis as one key piece of evidence that led to the arrest of a former IRS employee in connection with the 2023 murders of his wife and an unknown man in the idyllic Washington, D.C., suburb of Herndon, according to local reports.

Brendan Banfield, a husband and the father of a then-4-year-old daughter, and his family's then-22-year-old Brazilian au pair, Juliana Peres Magalhaes, are accused of killing Christine Banfield — Brendan's wife and Fairfax County NICU employee — and Joseph Ryan, the 38-year-old man who showed up at the Banfields' home armed with a knife, in Herndon, Virginia, in February 2023.

Ryan's connection to the family or their au pair remains unclear.

Fairfax Commonwealth's Deputy Attorney Eric Clingan told a courtroom on Sept. 27 that after investigators spent a year of reviewing "two definitive reports from expert forensic investigators," prosecutors determined they had enough evidence to prove their theory that Ryan and Christine's bodies were moved after death. Ryan's arms were moved and had Christine's blood on them, according to the Associated Press.

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Brendan Banfield is charged with four counts of aggravated murder and use of a firearm in commission of a felony. (Fairfax County Police)

John Carroll, an attorney for Brendan and Peres Magalhaes, argued that prosecutors' newfound evidence does not prove Brendan killed his wife and Ryan.

"It just doesn't add up, judge," he said in court on Sept. 27, as AP reported.

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Fairfax Circuit Chief Judge Penney Azcarate ultimately decided to deny bail for Brendan at the conclusion of last week's hearing.

Juliana Peres Magalhaes faces charges of aggravated murder and use of a firearm in commission of a felony. (Fairfax County Police)

Brendan Banfield, who was arrested last month more than a year after the double murders took place, is charged with four counts of aggravated murder and use of a firearm in commission of a felony.

Magalhaes, who was arrested about eight months after the killings, also faces charges of aggravated murder and use of a firearm in commission of a felony.

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"On Feb. 24, 2023, I stood in the middle of a cul-de-sac street in Fairfax County and described the deaths of two persons inside of a residential home. Now, 570 days later, we know the deaths of Joseph Ryan and Christine Banfield are, in fact, murders," Fairfax County Police Department Chief Kevin Davis said during a September press conference.

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

When police initially responded to a 911 call from the residence that day, they found Christine with stab wounds to the neck and Ryan with fatal gunshot wounds in the upstairs bedroom of the home. Authorities took Christine to the hospital, where she was later pronounced dead, Davis said.

Officials recovered a knife and two firearms from the scene.

VIRGINIA AU PAIR CHARGED IN MAN'S MURDER AT HOME OF DOUBLE HOMICIDE: POLICE

"We know Brendan Banfield and Juliana Magalhaes were involved in a romantic relationship at the time of the murders," Davis said during the September press conference. "I will not describe our victim, Joseph Ryan's, involvement with anyone in the case at the moment because this investigation continues," Davis said.

Fairfax County police initially responded to the double homicide in the 13200 block of Stable Brook Way in Herndon, Va., on Feb. 24, 2023. (FOX 5 DC)

On Feb. 24, 2023, Magalhaes told police she left the Banfields' home in the 13200 block of Stable Brook Way in Herndon to take their young daughter to the National Zoo. She told authorities that she had begun driving but realized she had forgotten the lunches she packed for their excursion inside the house, so she turned around and noticed an unfamiliar car in the driveway.

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She then reportedly called Brendan, a former criminal investigative agent for the IRS who had at that point left for work, and told him about the unknown car in their driveway. The pair decided to meet at the Banfields' home and walk inside together, as the Washington Post reported.

Juliana Peres Magalhaes (Instagram)

Initially, Magalhaes told police that when she and Brendan walked inside, they saw an unknown man, Ryan, holding Christine at knifepoint. She allegedly described him as an intruder. Ryan was apparently fully clothed while Christine was naked in the main bedroom of the house.

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It remains unclear exactly what transpired inside the home that Friday morning, but Magalhaes and Brendan apparently both admitted to shooting Ryan while the man was holding a knife to Christine.

Prosecutors allege that a computer at the Banfield home was tied to an account on a sexual fetish website, the Post reported.

Brendan Banfield faces charges of aggravated murder and use of a firearm in commission of a felony. (Virginia County Police Department)

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While the account on that computer appeared to show a photo of Christine in a bathing suit, it is unclear exactly who was communicating on the account. The profile also apparently did not display "one iota of evidence that she was into knife play, binding, BDSM," Clingan previously said in court, according to the Post.

Ryan, the man who reportedly held Christine at knifepoint, also apparently had an account on the website and had been communicating with whoever was accessing the site from the Banfield computer.

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

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Authorities arrested Magalhaes in October 2023 after she moved in to the Banfields' main bedroom and placed a framed photo of herself with Brendan on a nightstand beside the bed. A grand jury indicted the 23-year-old in April, and her trial is scheduled to take place in November.

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Magalhaes' attorney, Ryan Campbell, did not respond to an inquiry from Fox News Digital. Brendan is no longer employed by the IRS, the agency confirmed.