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.
The campus police officer who shot Robert Cameron Redus said the 23-year-old student got out of his truck after a traffic stop, approached the officer and got into the struggle which claimed Redus' life.
Redus' friends at the University of the Incarnate Word in San Antonio, Texas, say that's not the person they knew.
They knew a student who made the dean's list at the Catholic college and had been co-valedictorian of a Christian high school back home in Baytown, Texas. They knew a fun-loving campus television news anchor who was "the sweetest, kindest, gentlest person," as friend Annie Jones described him to CNN affiliate WOAI-TV.
Sarah Davis even attended a news conference at the Alamo Heights police station looking for information.
"The story just really doesn't make sense to any of us," she told CNN affiliate WOAI. " And I think we're mostly just angry and want answers."
The shooting took place Friday in an off-campus parking lot in the town of Alamo Heights, which neighbors San Antonio.
Redus was speeding and driving erratically, said Alamo Heights police Lt. Cindy Pruitt.
Incarnate Word campus police officers are permitted to use police powers off-campus, she said.
When the officer pursued Redus in his marked cruiser, the student pulled into an apartment complex.
A resident of the complex, 22-year-old Mohammad Haidarasl, told the San Antonio Express-News that Redus was his upstairs neighbor.
It was 2 a.m., and Haidarasl was on his apartment sofa.
He told the paper he heard a voice he believes to have been the officer's saying, "Stop resisting, stop resisting."
The newspaper quoted Haidrasl as saying he thought he heard a struggle and "then the cop said, 'I'm going to shoot.'"
A male voice replied, "'Oh, you're gonna shoot me?' like sarcastic almost," Haidarasl said.
Less than a minute later, he said, he heard shots.
Alamo Heights police acknowledged the officer fired several shots. But they would not discuss other details of the alleged struggle, citing the ongoing investigation.
CNN is not naming the officer because he has not been charged.
Redus' family released a statement to CNN affiliate KENS-TV saying, "We are understandably devastated by the death of our dear son Cameron and we ask for your prayers as we deal with our tragic loss. We trust that God is faithful and will see us through this most difficult time."
University President Lou Agnese said in a statement released to WOAI, "Our thoughts and prayers go out to the families of the student and officer involved in this incident."
Hundreds of people, including relatives of Redus, gathered at the university's convocation center Saturday for a vigil. Students brought a slideshow of Redus in happy poses.
"It makes me feel better that we've got a lot of support for Cameron," classmate Albert Salinas said outside the event in an interview withCNN affiliate KSAT-TV.
But they left with no better idea of what happened to their friend.