CONCORD, N.H. (AP) – Melanie Cooper remembers the day Eric Windhurst murdered her sexually abusive stepfather 21 years ago like it was a movie – from the telephone call telling her he was going to “do it” to the moments after the shooting, when he came sprinting through the woods, shouting at her to run.

It was all too unreal for a 15-year-old girl, she said Friday in court.

Infatuated with Windhurst and excited at spending the day with him, Cooper said she didn’t question him about his plan to murder her adoptive father as they drove from Hopkinton to Hooksett, not as he parked the car and smeared mud on the license plates, not even as he ordered her to stay behind as he walked away with a rifle in his hands.

“He was just in a movie world and just going through the steps,” she said. “I didn’t question it because I didn’t think it was going to happen.”

But it did, and for 20 years the case went unsolved, partly because she lied to police 14 years ago about Windhurst’s involvement in the Nov. 9, 1985, murder.

For that, Cooper, a Mormon mother of five now living in Evanston, Wyo., was sentenced Friday to three to six years in prison after pleading guilty to a charge of hindering arrest. Her cooperation beginning two years ago helped police arrest Windhurst in 2005, and in August he pleaded guilty to second-degree murder and ordered to serve at least 15 years in prison. But Judge Robert Lynn rejected a plea deal that would have kept Cooper, now 36, out of prison.

Some of Cooper’s estranged relatives – brothers, sisters, nieces and nephews of Danny Paquette who had asked Lynn to impose the maximum seven-year penalty – smiled as she was handcuffed and led away. One snapped a photo with his cell phone and called out “bye.”

Paquette relatives recounted their anguish living with an unsolved murder for 20 years.

“When Danny died, the rest us of have lived in fear, wondering, who’s next?” said Tamara Paquette, a niece, who described her father’s depression after his brother’s death.

“You used 21 years of our suffering to build a life,” said Jennifer Chassey, another niece. “I hope you carry the burden.”

Keith Bastek, Danny and Denise Paquette’s first-born, blamed his half-sister for taking his father away. Bastek was given up for adoption as an infant and reunited with his birth families after Danny Paquette’s death. He carried his father’s military uniform into the courtroom.

“I looked up my natural family to find my heritage … now I’ll never find that,” he said.

Cooper spent her childhood in fear of rapes and abuse by Danny Paquette that went unnoticed, and later, unreported by her mother. After divorcing in 1981, Denise Paquette took her daughters to Alaska, but Cooper returned to live with an aunt and uncle in Hopkinton in 1984. Cooper said it was fear of being found by Paquette after her return to New Hampshire that prompted her to confide in Windhurst, then 17. Unbeknownst to her, was dealing with revelations of sexual abuse in his own family. Cooper said it was Windhurst’s idea to kill Paquette.

“I just want to say how sorry I am for the loss of Danny,” a tearful Cooper said, facing the Paquettes and with her own children looking on.

“I did not ask for Danny to be killed,” she said. “Danny may have done a lot of things but he didn’t deserve to die the way he did.”

Slight and with dark circles under her eyes, Cooper spoke quietly, at times seeming barely able to get words out. She began to shake as she retook her seat.

Her husband, David Cooper, told the court his wife had suffered for years, from the abuse, then keeping silent over the murder. Reliving it all while working with investigators had taken a mental and physical toll on his wife, he said.

“She did tell me on more than one occasion it would have been easier to commit suicide than go through this,” he told the court. “I’ve seen her guilt over the years of what she knows.”

Cooper was allowed to say goodbye to her children before being taken to the Goffstown women’s prison. Lynn said he would support a transfer to a prison closer to Cooper’s home, if that is possible.

Prosecutors had recommended a suspended sentence because of Cooper’s unprecedented cooperation with investigators. Cooper worked with investigators for more than a year, traveling to New Hampshire several times, and made several taped phone calls to Windhurst for them.

However, Lynn questioned whether investigators, in their eagerness to solve the crime, had too readily accepted Cooper’s assertions that she never believed Windhurst would go through with the murder. Cooper – a star soccer player who was accepted to Dartmouth College despite academic struggles in high school – seemed too intelligent not to question Windhurst’s plan, Lynn said.

“I can’t help saying that candidly, I have very serious questions about the accuracy of what you had told me,” Lynn said.

Lynn also asked why Cooper agreed to go to Hooksett if she was afraid to be spotted by Paquette.

“I really had this crush on Eric and to me, when he called me – I was just thinking I’d spend the day,” she said. “He could have taken me anywhere.”