She exchanged 40,000 texts with her alleged killer. At his trial, they’re being used to tell two different stories

By Faith Karimi, CNN

(CNN) — Matthew Farwell wanted to stop by Sandra Birchmore’s apartment. Just for a little while.

“Are you still up?” he texted her. “Okay to come by for a second?”

It was the night of Feb. 1, 2021, as a snowstorm swept through eastern Massachusetts. Birchmore was about 10 weeks pregnant and had spent much of the day in her apartment in the Boston suburb of Canton, planning for life as a new mom. She’d ordered a stroller, searched for nursery furniture and texted a friend about newborn onesies.

When Farwell’s message arrived at 9:07 p.m., she didn’t hesitate.

“Yeah. You can come say hi. You okay?” she wrote back. “Door’s open when you get here.”

It was the last text she ever sent.

Seven minutes later, surveillance cameras captured Farwell entering her apartment building, where he stayed for about half an hour, prosecutors say. Birchmore was found dead three days later, slumped on her bedroom floor with a duffel bag strap looped around her neck and tied to a closet door handle. Local and state authorities ruled the 23-year-old’s death a suicide, but to her family, nothing about it made sense.

Federal prosecutors later reached a different conclusion. They charged Farwell, a former police officer in nearby Stoughton, with killing Birchmore and her unborn child. He has pleaded not guilty, and his trial is in its third week at the federal John J. Moakley Courthouse in Boston.

Birchmore and Farwell exchanged some 40,000 text messages in the years before her death, according to investigators who recovered them from her phone and laptop. The texts document their most intimate conversations and the growing tensions between them, and attorneys on both sides are using the messages to bolster their theories of the case to jurors.

Prosecutors say the messages reveal years of grooming and a sexual relationship that began when Birchmore was 15 and Farwell was 27. They argue that Farwell, then a married police officer, killed the young woman to keep her from exposing it. But the defense says the messages suggest a different story: that Birchmore was unstable and died by suicide after Farwell ended their relationship.

Birchmore was rarely without her phone and was a frequent texter, her cousin, Angelique Pirozzi, told CNN earlier this year.

“She was outgoing and very passionate about her friendships,” Pirozzi said. “She overshared — she texted people constantly.”

Birchmore died more than five years ago. But the messages she left behind — including 600 texts prosecutors say she sent or received in her final hours — may help the jury decide what happened on that winter night in 2021.

“It’ll come across like she’s speaking to them (jurors) from the grave,” says Chris Dearborn, a law professor at Boston’s Suffolk University. Even in the digital age it’s “highly unusual” for authorities to have years of private messages detailing the history of a relationship, he tells CNN.

“That could be powerful evidence as long as it’s not overdone,” adds Dearborn, who has been following the trial. “They (prosecutors) want to create as strong a motive as possible, because the forensic evidence isn’t airtight.”

The texts revealed tensions over her pregnancy

Before jurors heard from witnesses or saw any exhibits, both sides were already pointing to the text messages as key evidence.

In their opening statements earlier this month, prosecution and defense attorneys mentioned the texts 33 times while describing sharply different accounts of Birchmore’s relationship with Farwell. The next week, a male and female FBI agent took turns reading the texts aloud in court. Birchmore started a majority of the conversations, and Farwell sometimes blocked her on his cellphone, FBI Special Agent Heidi Kelsch said, according to CNN affiliate WCVB.

Farwell, 40, is charged with killing a witness or victim to stop Birchmore from potentially exposing his alleged grooming and sexual abuse of a minor. He also faces a second charge – related to Birchmore’s pregnancy – of violating a federal law protecting unborn children.

Farwell was decertified as a police officer and has been barred from working in law enforcement in Massachusetts.

Tensions between Farwell and Birchmore escalated in December 2020, after she told him he was pregnant and he was the father. Prosecutors say Farwell believed he was the father in the weeks before Birchmore’s death, and that she had previously threatened to expose their relationship if he did not impregnate her.

But a DNA test after her death found that a US Army recruiter — not Farwell — was the father of the unborn child, investigators say. The recruiter, Jason Pickard, testified last week that Birchmore told him she believed Farwell was the father and that he only learned last year that the child was his, according to WCVB.

The paternity finding has become a key part of Farwell’s defense. His attorney pointed to a text message Birchmore sent Pickard in late January, saying they needed to talk. The defense suggests Birchmore intended to tell Pickard he was likely the father and that Farwell knew the child wasn’t his, undermining prosecutors’ claim that he had a motive to kill her.

Text messages between Birchmore and Farwell capture how differently they viewed her pregnancy, prosecutors say. Birchmore sent him an image of a handmade poster decorated with cartoon jungle animals. “Congrats we are goin’ to be parents!” it says.

Farwell did not sound thrilled. “You are truly the worst person on the face of the earth,” he texted back.

It’s not clear whether Birchmore ever learned who the father of her child was. But prosecutors say she’d told more than 80 people she was expecting, and that the pregnancy marked a turning point in her relationship with Farwell.

Birchmore later texted Farwell a list of expectations: She wanted the child to have his last name, and she wanted him present for the birth and for a few days around Christmas and Easter, according to federal documents. In text messages, Farwell repeatedly told her he’d prefer to have conversations about the child in person.

Birchmore also began texting Farwell about some of their earlier sexual encounters, when she was a minor, to create a digital record of his behavior, her cousin, Barbara Wright, told CNN earlier this year.

“She was starting to wake up to the fact that what was going on was completely and totally wrong and that maybe she could do something about it,” Wright said.

Authorities say the changing tone of Birchmore’s text messages showed she was becoming more assertive and less willing to do as Farwell wanted.

“She kept changing the terms of the deal. She kept asking for more,” Assistant U.S. Attorney Torey B. Cummings told jurors in her opening statement. “The defendant was not happy about it, but he was trying to appease her in order to keep her quiet.”

But the defense says the texts portray a young woman who was struggling financially and emotionally, and was desperate to have a baby with Farwell.

“This is going to be a difficult journey that we all take together,” defense attorney Kimberly Stevens told jurors in her opening statement. “It’s hard to hear evidence of mental health struggles and challenges and sadness and obsession, despondency and suicide.”

Stevens said Birchmore sent Farwell a flurry of messages in the days leading up to her death. On January 31, she texted:

“I’m needy today. And I don’t feel good.”

“It’s okay. I’m hoping I feel better after dinner. I just need to eat.”

“Can we talk tonight for a little bit before I go to sleep? Can I text you tomorrow before the snow comes?”

“I wish you were here with me tonight.”

“I keep waking up.”

The texts continued on February 1 and until shortly before Farwell asked to come over, Stevens said.

“That’s a window into her mental state as this is all happening,” Stevens told jurors, suggesting that Birchmore was in a vulnerable state after spending the holidays alone and pregnant. “She’d expressed fears that her pregnancy was at risk.”

Farwell asked her to delete their texts, prosecutor says

Farwell’s defense has not challenged the authenticity of the text messages but has accused prosecutors of presenting “hand-selected” excerpts to jurors.

The defense also has argued that forensic evidence found at Birchmore’s apartment does not support the prosecution’s account of her death. When she was found, Birchmore’s clothes did not show tears or other signs of a struggle, Stevens said. Farwell’s DNA was not found under her fingernails, and the ligature around her neck contained DNA from several people – not just Farwell — Stevens added.

But prosecutors say messages between Farwell and Birchmore often referenced violent sexual activities, including strangulation, and suggested she wouldn’t have suspected Farwell was trying to kill her if he put his hands or a duffel strap around her throat that night.

“The messages are really the best motive evidence they (prosecutors) have. You don’t need motive in a murder case, but it’s really hard to convince a jury when you have a circumstantial case that somebody did something unless you establish clear motive,” says Dearborn, the Suffolk law professor. “So if they’re believed and handled properly, the text messages … connect the circumstantially forensic evidence to his motive.”

Farwell had repeatedly told Birchmore to delete their text conversations from her phone, Cummings told jurors. They included messages referring to her losing her virginity to him when she was 15, prosecutors say.

After Birchmore’s death, Matthew Farwell said he wiped his phone to delete evidence of his communications with her, his twin brother, William Farwell, testified Tuesday.

But investigators eventually retrieved years of messages from Birchmore’s digital devices, Cummings says.

They included angry messages from Farwell sent about two weeks before Birchmore was found dead. In January of 2021, a friend of Birchmore’s contacted the Stoughton Police Department and reported the sexual relationship with Farwell, according to federal documents. Farwell was outraged when he learned about the call and knew it was only a matter of time before their relationship was exposed, prosecutors said.

He sent her a flurry of messages. “Dude, your f***ing friend called my job Sandra wtf,” one of them said. Another said, “You also told me that no one knew about us.”

“The defendant knew he had a problem,” Cummings told jurors. “The defendant had to solve this problem. He had to get rid of it.”

The prosecutor also pointed to text messages Birchmore sent a friend days before she died, suggesting they were incriminating evidence of Farwell’s intent. During one of his last visits to her apartment, Birchmore texted the friend that she noticed him inspecting her bedroom closet and bathroom and she thought it was “really weird.”

Her body was found near the same closet.

What thousands of messages can — and can’t — reveal

The thousands of text messages may help the jury see a fuller picture in Birchmore’s case. But there’s also the risk of overwhelming jurors, experts say.

“A large collection of messages can reveal patterns and provide important context,” says Xinwen Fu, professor of computer science at the University of Massachusetts Lowell. “However … attorneys must select which conversations to present, creating a risk of selective interpretation and conflicting narratives.”

Context and corroboration with other evidence is key, he says.

Text messages can capture honest emotions, but they can also contain exaggerations that can be misunderstood without context, experts told CNN. During a trial, it comes down to how jurors interpret the texts and how they fit with the rest of the evidence, Fu and other experts said.

“The significance of 40,000 messages lies less in their sheer volume than in whether their content and timing connect reliably with the physical evidence,” says Kyung-shick Choi, director of cybercrime and cybersecurity at Boston University Metropolitan College. “Digital records can help reconstruct a timeline, but establishing what happened ultimately depends on how well the various forms of evidence corroborate one another.”

In Birchmore’s case, Choi adds, the messages could be especially revealing because they offer a glimpse into what she was thinking and experiencing at the time. “Digital communications can be particularly influential when they preserve exact language and timing,” he says.

But the messages have their limits. A text expressing despair doesn’t prove someone died by suicide, just as one expressing hope doesn’t rule it out, Choi says. The thousands of messages reveal much about Birchmore’s life and her relationship with Farwell, but they cannot prove to jurors what happened to her, he says.

Prosecutors also pointed to Birchmore’s internet search history to refute the defense’s suggestions that she was suicidal.

Investigators found hundreds of baby-related searches on her phone and computer in the weeks before her death, but none on ways to commit suicide, “or for how someone might kill themselves by hanging from a doorknob while seated on the floor,” Cummings told jurors.

And despite how much of her life Birchmore shared through her texts, there’s one thing prosecutors say she didn’t leave behind.

“There was no suicide note,” Cummings told jurors. “The girl who told everyone everything about her life left no note.”

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