FAIRFAX, Va. — A Brazilian babysitter who fell in love with an IRS agent pleaded guilty Tuesday to involuntary manslaughter in what prosecutors said was an elaborate double-murder plot to frame another man for stabbing his wife.

For months after the murders on February 24, 2023, Juliana Peres Magalhäes and IRS agent Brendan BanfieldHe got away with the murders, according to new details prosecutors revealed in court to support his guilty plea.

Christine Banfield, a pediatric intensive care nurse with a 4-year-old daughter, was fatally wounded with stab wounds to her neck, and Brendan Banfield, her husband, and their live-in nanny had shot her apparent killer — a man. Lured into the bedroom with promises of rough sex.

Magalhäes had called 911 to the Herndon, Virginia, home and was breathless at the scene as he described the murders.

Detectives didn’t believe it, but it took time to build the case. Meanwhile, the live-in caregiver moved into the master bedroom with Banfield and posted photos of them as a couple, authorities said. When she was arrested in October 2023, there was a photo of her with Brendan Banfield on her bedside table.

And he refused to say anything more afterward, as he remained in prison for more than a year.

The long-awaited forensic report blood spatter evidence came later and prosecutors said it showed Brendan Banfield smearing blood from Christine Banfield’s wounds onto the body of Joe Ryan, whom they were trying to accuse of stabbing Christine Banfield. Authorities arrested Brendan Banfield on aggravated murder charges in September.

Banfield’s attorney, John F. Carroll, told the court before he was denied bail in September that the evidence “does not suggest” he killed his wife.

In October, Magalhäes agreed to cooperate with police in his second interview since the day of the crime. Days later, on Tuesday, two weeks before she was due to go on trial on charges of second-degree murder and aggravated use of a firearm, Magalhäes pleaded guilty to Ryan’s murder, saying she agreed to help her husband’s ruse to murder his wife and kill her. Both appear to have shot a predator.

“Do you plead guilty because you are actually guilty of this crime?” Chief Judge Penney Azcarate considered the motion before accepting Magalhäes’ plea for a reduced count of single counts of manslaughter, murder and firearms offenses.

“Yes,” he replied softly.

The sentence for Magalhäes, who grew up on the outskirts of Sao Paulo, now awaits the outcome of Brendan Banfield’s trial. Depending on his cooperation with authorities, the lawyers told the court they might agree to sentence him to prison for the amount of time he has already served.

“Much of the information that led to this settlement cannot be made public at this time due to the pending criminal prosecution against the co-defendant in this matter,” said Fairfax County Commonwealth’s Attorney Steve Descano.

Prosecutors, who laid out facts Magalhaes confirmed in court, said he made multiple calls to 911 that day. The first lasted several seconds, not a word; only someone’s guttural moan could be heard in the background. About 15 minutes later, another call came in saying the intruder had stabbed his friend. Brendan Banfield said he then picked up the phone and shot a man who stabbed his wife.

An officer’s body camera footage filed in court last month shows Magalhaes on his knees in the driveway, seemingly dazed and unable to even catch his own breath.

“There was so much blood,” Magalhäes said while hyperventilating. “Brendan said ‘Please put the knife down, put the knife down’ because he had a knife in his hand.”

He later told detectives that he shot the intruder in the chest after Brendan Banfield shot him in the head.

But in court Tuesday, prosecutors claimed the woman lied as part of a ruse to lure someone else into the home to be accused of her wife’s murder.

Magalhäes began working for Banfields in late 2021, affidavits say. Assistant Commonwealth’s Attorney Eric Clingan told the court the babysitter and the husband began having an affair in August 2022. Shortly thereafter, Brendan Banfield began conspiring to kill his wife, Clingan said. .

To cover up the ruse, Clingan claimed that Brendan Banfield created a profile for his wife on a social networking platform for people interested in sexual fetishes and matched her with Ryan. They soon began chatting via Telegram, an encrypted messaging app, and Magalhãoes pretended to be Christine Banfield in the voice conversation. Ryan agreed to come to the house for what appeared to be a consensual sexual encounter.

“At various points prior to the 24th, Peres Magalhäes stated to Brendan Banfield that he did not believe he would carry out this plan and at other times told him that he did not want to proceed,” Clingan said. “But he insisted it was too late for him to back down now.”

Clingan said Magalhäes and Brendan Banfield left the girl in the basement and then followed Ryan into his bedroom, armed with guns.

Authorities monitored his phone calls from the Fairfax County jail. In a meeting last month, Clingan said Brendan Banfield’s mother, who is paying for the babysitter’s legal defense, discussed the consequences that prison ‘snitches’ would face.

In another, between Brendan Banfield and the babysitter, Magalhâes said: “I hope you’re not just staying with me because you’re afraid I’ll turn against you.”