A Florida woman accused of deliberately crashing an SUV with her boyfriend inside was furious over another girl’s text messages before making a sharp turn into the woods at nearly 100 mph, prosecutors told jurors Tuesday.
But Leigha Mumby’s defense attorney offered a different explanation as her trial opened, suggesting something happened inside the vehicle that she neither anticipated nor controlled.
Mumby, 25, has pleaded not guilty to vehicular homicide and reckless driving causing serious bodily injury in the death of Daniel Waterman, 22, who survived the crash, but died eight months later.
Assistant State Attorney Melissa Clark told jurors the couple had left a Super Bowl party before the Feb. 9, 2025, wreck on Interstate 95 in Flagler County, according to proceedings livestreamed by Court TV.
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Clark said the SUV traveled at speeds exceeding 100 mph before the crash. Vehicle data showed it was moving at 94 mph in the final seconds before an “abrupt, left-hand turn at 45 degrees” sent it off the highway and into the woods.
The prosecutor described the turn as “a dangerous and reckless maneuver.”
Waterman suffered a broken neck that left him paralyzed from the neck down, Clark said. He fell into a coma and, after awakening, could not breathe on his own.
His death on Oct. 8, 2025, was “directly related and caused by this crash,” Clark told the jury, who will not hear Waterman’s own account of the crash that he told detectives before he died.
He told investigators from his hospital bed that Mumby deliberately swerved off the road following an argument over another woman’s text message. A judge ruled those statements inadmissible, leaving prosecutors unable to present his version of events at trial.
Defense attorney Reid Hart called the case a “pure and utter tragedy” and urged jurors to consider whether the SUV’s sudden change in direction resulted from something outside Mumby’s control.
“The crux of this trial effectively comes down to one steering wheel input, and ultimately one question,” Hart said, according to Court TV’s livestream.
Hart questioned whether Mumby chose to drive off the road or whether something happened inside the vehicle that “she did not expect, she did not anticipate, and she did not control.”
He argued that once the vehicle began careening toward the woods, she could not stop it despite trying to avoid the crash.
Jurors also heard Tuesday from Sarah Stappenbeck, Waterman’s cousin and Mumby’s best friend, who hosted the Super Bowl gathering.
Stappenbeck testified that Mumby announced earlier that day that she had learned she was pregnant. But the news came alongside concerns about Waterman’s contact with other women.
Mumby “expressed concerns of Daniel talking to other girls and said that she wasn’t going to let Daniel cheat on her,” Stappenbeck testified.
The couple left before the game ended. Within about 20 minutes, Stappenbeck said, Mumby called her, yelling that Waterman was texting another girl and that she planned to bring him back to the house.
“She’s yelling at me,” Stappenbeck recalled.
Stappenbeck said she did not hear Waterman speaking in the background. She tried to calm Mumby and urged the couple to get home safely and address their disagreement the following day.
“She just said that ‘You’re taking his side,’ and hung up with me,” Stappenbeck testified.
About 20 minutes later, Mumby called again, still angry, and repeated that she was bringing Waterman back, Stappenbeck said.
They never arrived. Instead, Stappenbeck testified, Mumby’s roommate called and told her to go to the hospital because there had been a crash.
The trial is unfolding without Waterman’s account to investigators of what happened inside the SUV.
Before his death, Waterman told detectives Mumby deliberately caused the wreck after an argument over a text from another woman, according to charging documents previously reported by Court TV.
He said the last thing he remembered was Mumby telling him, “I don’t care what happens, you’ll get what you deserve,” before swerving off the road.
Judge Dawn Nichols ruled those statements could not be introduced at trial. Prosecutors said they wanted jurors to hear Waterman’s account, but acknowledged the rules of evidence prevented them from using it at trial, Court TV previously reported.
“The court is bound by the law and the court is bound by the rules of evidence,” Nichols said when explaining the ruling.
The first day of Mumby’s trial also brought an emotional moment for Waterman’s family. His mother, Heather Waterman, was seen wiping away tears as a photo of her son was shown in court.
Court adjourned for the day following Tuesday’s proceedings.
Mumby was initially arrested in July 2025 on charges of reckless driving causing serious bodily injury and aggravated battery with a deadly weapon.
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After Waterman died, prosecutors upgraded her charges to include vehicular homicide. She was booked into the Flagler County Jail and released after posting a $150,000 bond.
Waterman’s mother previously told Syracuse.com that he spent time in a coma before recovering enough to tell investigators what happened.
Waterman’s aunt, Tiffany Waterman, expressed anguish over the exclusion of her nephew’s statements in a Facebook post Monday as jury selection began.
She remembered his efforts to comfort a loved one watching a movie beside him in his hospital bed, smiling at her while trying to conceal his pain.
“That’s who Daniel was. Protective, loving, and sweet,” she wrote. “He had the biggest heart, even in those last moments of life.”
The family previously told Fox News Digital through attorney John Hager that they supported the charges filed following Waterman’s death.
“There are no real winners in this situation. It’s a terrible, horrible situation,” Hager said in November 2025, adding that the family believed the charges were “right and just.”
Mumby gave birth to a baby girl three days after Waterman died, according to WSYR.
“Daniel was an excited, soon-to-be father of a baby girl,” his obituary said. “He wanted nothing more than to come home to her and to the family who loved him so dearly.”
The trial comes amid renewed attention to another deadly crash involving a young woman convicted of intentionally driving into a building with her boyfriend inside.
Mackenzie Shirilla is serving two concurrent sentences of 15 years to life for killing her boyfriend, Dominic Russo, 20, and their friend, Davion Flanagan, 19, in a 2022 crash in Strongsville, Ohio, Fox News Digital previously reported.
Shirilla’s case became the subject of Netflix’s “The Crash.”
She was convicted in 2023 after prosecutors argued she deliberately drove into a brick building at nearly 100 mph to end her relationship with Russo.
The Ohio Supreme Court recently rejected her request to reconsider its decision, declining to hear her latest appeal. Shirilla has maintained the crash was not intentional.
Fox News Digital’s Michael Sinkewicz, Greg Norman, and Stephen Sorace contributed to this report.
