The defense and prosecution agree on this much: Jordan Linn Graham pushed her husband of eight days, and he fell off a cliff to his death in Glacier National Park in Montana.
The question for jurors will be whether Graham's act was murder or an accident caused by self-defense.
Graham's trial is scheduled to begin with jury selection Monday in U.S. District Court in Missoula, Montana,
Cody Johnson, 25, disappeared July 7. Four days later, the FBI says, Graham led friends and relatives to a popular spot in the park, where they found Johnson's body.
The 21-year-old new bride at first maintained she had simply speculated Johnson might have gone there. But an FBI agent said that she changed her story when she was shown a surveillance photo of the couple entering the park together.
"Bottom line is eight days after you're marriage, you have surveillance photos of both of them walking into the park, he ends up dead at the bottom of a cliff and she tells no one. That's really all I need."
What exactly Graham said next to the FBI will be fiercely contested at the trial.
At a pre-trial hearing November 15, Graham testified, "We went on a little stump part and we were in the middle of an argument and he thought I was going to run away. Cody had grabbed me and I thought he was going to push me down. My first instinct was to get him off."
In a court fiilng, the defense said Graham pushed Johnson away as she removed his hand from her arm, and her husband tumbled over the cliff.
But the criminal complaint against her says that in an FBI interview, "Graham stated she could have just walked away, but due to her anger, she pushed Johnson with both hands in the back and as a result, he fell face first off the cliff."
Her attorney, federal public defender Michael Donahoe, said the FBI did not record the first hour and 20 minutes of Graham's interrogation. He accused an FBI agent of then making "an epic effort" to get Graham to use "key words" in a recorded session that would support a criminal conviction.
A defense motion says that in two subsequent recorded FBI interviews, Graham said she acted in self-defense and that her husband's fall was an accident.
Graham, who had been a part-time nanny, is accused of murder and making false statements.
The case is being prosecuted in federal court before U.S. District Judge Donald W. Molloy because the incident occurred in a national park.