Brendan Banfield case: How an au pair affair and a fetish website factored into a Fairfax County double murder and a 10-year sentence

brendan banfield, an IRS agent at the center of a high-profile Fairfax County homicide case, was connected to a scheme that used an online fetish profile and an extramarital affair; the au pair who helped execute the plan was sentenced to 10 years in prison this week.

Brendan Banfield and the timeline of the double killing

The violence unfolded on a winter morning in February 2023 at the Banfield family home in an affluent northern Virginia neighborhood. Investigators found Christine Banfield bleeding from seven stab wounds to the neck and a man later identified as Joseph Ryan fatally shot with wounds to the head and chest. The homeowner said he came home to find Ryan stabbing his wife and said he used his government-issued firearm to shoot Ryan before rendering aid; the family’s Brazilian au pair told authorities she also shot Ryan while the couple’s 4-year-old child was left in the basement.

The events that preceded the killings included contact on a sexual fetish website, where a profile under a pseudonym and showing a single photo of the married mother was used to lure one of the victims. Investigators later questioned whether that profile had been created by the mother. Digital evidence and message phrasing drew investigators’ suspicion as they reconstructed how the contact developed into an in-person encounter at the Banfield home.

How the au pair affair and online impersonation factored into the plot

The au pair, who later pleaded guilty to manslaughter in the death of Joseph Ryan, testified about an affair with Banfield and about creating an online profile that impersonated the wife to entice the victim to the home with promises of rough sex. Prosecutors say the profile and messages were instrumental in luring Ryan to the house on the date of the killings.

Months of investigation and a second search warrant executed in October 2024 revealed further disturbing details. Investigators found that the au pair had moved into the primary bedroom, removed photos of the victim, and placed a framed picture of herself and Banfield on the nightstand; clothing and lingerie belonging to the au pair were found throughout the room, creating the impression that she had replaced the wife in the household.

Sentence, plea deal and fallout for Brendan Banfield

The au pair received a 10-year sentence after pleading guilty to manslaughter. A plea agreement had included a recommendation for time served in exchange for cooperation and testimony, but the presiding judge rejected that recommendation and imposed the maximum penalty allowed. The judge described the case as an intentional and calculated level of violence and noted the gravity of the facts presented at sentencing.

brendan banfield was later found guilty of aggravated murder and other charges, including use of a firearm in the commission of a felony and child endangerment tied to the presence of the couple’s young child during the killings. He faces life in prison with no chance of parole and is scheduled for sentencing on May 8.

What investigators say the evidence shows and what remains open

• Digital messages and an online profile under a pseudonym were used to arrange an encounter at the Banfield home.
• Physical evidence at the scene included stab wounds to the wife and fatal gunshot wounds to one of the men involved.
• Later searches found signs that the au pair had established herself in the primary bedroom and removed the victim’s belongings.
• The au pair cooperated with prosecutors and testified at trial, and she accepted a reduced charge in exchange for that cooperation.

Certain aspects of motive and the full sequence of actions inside the home were contested and required months of investigation and courtroom testimony to resolve. Recent legal proceedings have produced convictions and a sentencing for one co-defendant, while the central defendant faces a life sentence. Further developments tied to pending sentencing and any appeals could alter the public record.

Timeline (key events drawn from court and investigative records):

• Winter 2023: Fatal attack at the Banfield home discovered by responding officers.
• Feb. 24, 2023: The man who went to the home had sought an encounter arranged through an online fetish profile.
• October 2024: Second search warrant executed; au pair arrested and charged with second-degree murder; investigators documented replacement of the wife’s belongings in the primary bedroom.
• October 2024 onward: The au pair pleaded to manslaughter and later testified about her role and an affair with Banfield.
• Recent: The au pair was sentenced to 10 years in prison; brendan banfield was convicted and is scheduled for sentencing on May 8.

This case underscores how online deception, intimate relationships, and escalating violence intersected in a plot that resulted in two deaths, a lengthy investigation, and convictions. Details from trial testimony and forensic work were central to securing convictions, and sentencing in the remaining proceedings will determine the final legal outcomes.