Digital and DNA evidence take center stage on day 3 of au pair affair murder trial

Brazilian au pair testifies against former employer and lover in double homicide case

During the third day of the murder trial of Brendan Banfield, who’s accused of carrying out an elaborate plot to kill his wife and another man so he could be with his au pair, jurors in the Fairfax County courtroom saw photos showing major changes inside the Banfield home in the months after the killings.

Photos showed that clothes and pictures of the au pair, Juliana Peres Magalhães, had been moved into the home’s master bedroom.

“They had gotten new flooring, new bedroom furniture. And pictures that had once featured Brendan and Christine had been taken down and replaced with Brendan and Juliana together,” Sgt. Kenner Fortner with Fairfax County Police Department said during trial Thursday.

Fortner took crime scene photos on the day of the killings, and compared those to photos taken when he returned months later.

The prosecution appeared to use the photos to point to a relationship at the center of the case — an alleged affair between Brendan and Magalhães that they say began before the killings. Prosecutors say Brendan Banfield and Magalhães plotted to kill his wife Christine, along with Joseph Ryan.

Ryan was allegedly lured to the home through a fetish website account created in Christine’s name.

Banfield faces aggravated murder charges.

Also testifying was the window salesman who sold the Banfields’ new windows a few months before the killings.

The salesman told jurors his company installed triple-pane windows months before the murders, and that an order of double-pane windows was changed to triple pane before the install. The defense pressed him on whether noise was ever discussed and whether the sound from Dulles International Airport or a nearby firehouse may have been the motive behind the upgrade.

“When someone goes to a triple pane, that’s another level, and that is a type of level where they’re trying to do more than just protect the house from the sun,” Matthew Niederriter said.

Magalhães told the court in testimony earlier this week that Brendan changed the windows in the home to make it more soundproof in preparation for the killings.

Others heard from an employee at a shooting range who said Brendan Banfield bought a gun from the range in the months before the killings, and that he and Magalhães were listed as visiting the shooting range in late 2022.

Christine Banfield and Joseph Ryan were killed in February 2023.

Virginia Department of Forensic Science forensic expert Cara McCarthy testified that two Glock handguns that were seized from the home were in working order.

A DNA expert followed, saying Christine Banfield’s DNA was found on Brendan’s jeans and Juliana’s shoes, and Joseph Ryan’s blood was on the carpet and wall.

While the prosecution did most of the questioning, the defense asked several questions that focused on how evidence was collected and whether procedures were followed correctly in evidence collection.

Magalhães admitted earlier this week that she helped plan the attack and pleaded guilty to manslaughter. She’ll be sentenced after the conclusion of the trial.

The trial will resume Tuesday.

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Mike Murillo

Mike Murillo is a reporter and anchor at WTOP. Before joining WTOP in 2013, he worked in radio in Orlando, New York City and Philadelphia.

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