Amanda Hayes tells jurors she did not kill Laura Ackerson

Full video: Amanda Hayes testimony

It wasn't until six days later, she said, that she realized Laura Ackerson – who was involved in a bitter child custody fight with Grant Hayes – had died.

By that time, the Hayes and the children had taken a trip to see her sister in Richmond, Texas, and Grant Hayes was looking get rid of the 27-year-old's dismembered remains.

The couple was outside late one night, Amanda Hayes said, when he told her what had happened and that "none of us were going to make it back to North Carolina" if she didn't help him figure out a way.

"I was freaking out. He had a machete, and he wacked me on the leg and told me to shut the 'F' up and that this was not the time for me to start challenging him," Hayes said.

Concerned for her safety as well as that of her 2- and 3-year-old stepsons and her 1-month-old and 22-year-old daughters, Amanda Hayes said, she didn't ask questions and did what she was told.

The next morning, she confessed to her sister that she was responsible for Ackerson's death.

"I was just really scared. I didn't even know how to tell her," Amanda Hayes said. "I just blurted it out. I told her something really bad happened and I needed her help."

Breaking down on the stand, Amanda Hayes also said that her husband's demeanor changed – with him even threatening to throw their baby out of an SUV window – after he disposed of Ackerson's body in the alligator-infested creek where Texas authorities recovered the head, torso and parts of her legs.

"Grant just started progressively getting a little crazier," she said. "By the time we started heading back to Raleigh, he was really very paranoid."

At one point, she said, he talked about them taking pills so that "they would all go to sleep" and on another occasion, threatened to slit Amanda Hayes' throat if she told anyone what happened.

"I pretty much spent the entire trip back praying for God to keep us safe," Amanda Hayes said.

But how exactly Ackerson died – an autopsy found signs of asphyxiation and a stab wound to the neck – Amanda Hayes did not say.

On the night of Ackerson's death, she said, Grant Hayes had her leave their third-floor apartment with the children after Ackerson tripped on a rug and hurt herself.

Because Grant Hayes didn't want the boys – they had been watching "Cars" in a bedroom – to see their injured mother, he moved Ackerson into a hallway bathroom so they could leave.

When she returned home later that night, Grant Hayes, Amanda Hayes said, reassured her that "everything was fine." Ackerson was actually OK and had left.

It was while sitting on the tailgate of her nephew's pickup truck in Texas, however, that Amanda Hayes' husband told her he had taken Ackerson's body to Kinston – where Grant Hayes' family owned several rental properties in the area.

"I'll never forget it. He was really calm. He said to me, 'What would you say if I told you Laura was dead?'" Amanda Hayes said. "Basically, he told me the night Laura had come over to the house, she had died, and whenever I left, he panicked and freaked out."

Nobody was going to believe a white woman dying in a black man's apartment was an accident, Amanda Hayes recalled her husband telling her.

Amanda Hayes also described her two-year relationship and 14 months of marriage to Grant Hayes, whom the defense says is a sociopath who manipulated his wife and spent all her money.

The couple met in late 2009 while they both lived in the Virgin Islands, Amanda Hayes testified.

She ran an art supply store and worked at a museum. He was a musician whom she met at a bar. They dated for a while, and in December of that year, she moved to Manhattan.

Grant Hayes, followed in January 2010, and several months later, they married and moved to Raleigh, where he and Ackerson fought most of the legal battle over their sons.

But the custody dispute and Grant Hayes' unemployment began taking its toll, Amanda Hayes said.

By December 2010, she was out of more than $180,000 that she had inherited from a former husband who died. She had paid for everything they had, she said, and Grant Hayes had also talked her into giving him $50,000 so that he could start a business selling designer iPod cases.

"I'm completely broke," she recalled. "He has not worked at all. There was no money coming in."

Grant Hayes, she said, also persuaded her to let him pawn off her jewelry to help pay both his legal bills and for a court-ordered psychological evaluation in the custody case.

They had been living off credit cards by mid- 2011, had amassed more than $20,000 in credit card debt and were in the process of being evicted from their apartment.

Eight months' pregnant at the time, Amanda Hayes said, she had considered leaving her husband.