Marissa Shephard has been found guilty of killing Moncton teen Baylee Wylie nearly two and a half years ago, and his family said justice has finally been served.

The jury delivered its unanimous verdict Tuesday to a packed courtroom after about four hours of deliberations.

Shephard was found guilty of first-degree murder and arson with disregard for human life in the 2015 death of Wylie, 18.

Firefighters discovered his body beneath a mattress in Shephard's burned-out Moncton townhouse on Dec. 17, 2015.

He had suffered more than 140 "sharp-force injuries" — most of them while he was still alive, the trial heard.

Shephard, 22, of Moncton, was the last of three people accused of killing Wylie to be convicted.

Seated quietly in the prisoner's box Tuesday, she showed no reaction to the verdict.

Marissa Shephard's father, Dave Shephard, had little to say to reporters outside the courthouse. (CBC)

Her father, Dave Shephard, whispered, "I'm not surprised" moments after the verdict was read.

Outside court, he said only, "I'm a biker, I don't get rattled that f--king easy."

'Light at the end of the tunnel'

Members of the Wylie family, who sat front and centre during the two-month trial, burst into tears as the verdict was read.

His mother, Amanda Wylie, cried throughout the reading of the verdict, her hands shaking.

She was accompanied by several emotional supporters including her sister, Angela Wylie, who told reporters it was too soon for comment.

Angela Wylie, the murder victim's aunt, met reporters outside the Moncton courthouse. (Tori Weldon/CBC)

About three hours later, she sent a written statement on behalf of the family.

"That light at the end of the tunnel has been reached and justice for Baylee has been served," it said.

"This has been a long and difficult process and the assistance of all of you who came to court, sent messages or shared their stories, you have made a (difference) and for that we thank you."

The family thanked the RCMP, singling out the lead investigator, Sgt. Jean Belliveau, as well as the Moncton Fire Department, victim services, Crown prosecutors Annie St. Jacques and Eric Lalonde, the news media "for their help and respect," court personnel and the public "for their continued support."

"We would also like to thank the jury, who spent months of their time on this case."

'They're just kids'

'It's sad for everyone,' said lead investigator Jean Belliveau, who called the jury's decision a good verdict. (Gabrielle Fahmy/CBC)

The lead investigator told reporters outside the courthouse that he thought the jury reached a good verdict.

"A lot of work was put into it," said Belliveau. "We had probably 70 people working on it at some times. It was a long haul, it was during Christmas."

He also described the case as a sad story for everyone involved.

"They're just kids, you know," Belliveau said. "I have kids their age. They made some bad decisions."

Judge calls trial 'fair enterprise'

The body of Baylee Wylie, 18, was found in a burned-out townhouse in Moncton on Dec. 17, 2015. (Submitted)

Court of Queen's Bench Justice Zoël Dionne thanked the jurors for their service.

"I was comforted in seeing Shephard was represented with strength," he said. "As well, the state was well represented by counsel. … For what it's worth, I feel it was a fair enterprise."

Shephard is scheduled to be sentenced on June 22 at 1:30 p.m.

First-degree murder carries an automatic life sentence with no chance of parole for at least 25 years.

But the Crown said Wylie's family wants to prepare victim impact statements, and the defence requested a pre-sentence report.

2 others convicted

The Crown had appealed the sentence Tyler Noel received for his second-degree murder and arson conviction, but subsequently abandoned the appeal. (N.B. Crime Stoppers)

Two other people were previously convicted of murder in Wylie's death — Devin Morningstar and Tyler Noel.

Morningstar, 20, is serving a life-sentence with no chance of parole for 25 years after being found guilty of first-degree murder and arson with disregard for human life. He appealed his conviction last summer, but lost.

Noel, 20, is serving a life sentence with no chance of parole for 16 years after pleading guilty to the lesser charge of second-degree murder and arson with disregard for human life.

The Crown had appealed Noel's sentence, describing it as "inordinately low, demonstrably unfit and clearly unreasonable," but dropped the appeal in February, saying the sentence was "neither illegal, nor the product of error, nor demonstrably unfit."

Twisted relationship

Devin Morningstar, 20, unsuccessfully appealed his first-degree murder and arson conviction last summer. (Facebook)

Morningstar was called three times to testify at Shephard's trial but refused each time he was brought into the courtroom.

Instead, the jury heard his videotaped police interview from the day of his arrest on Dec. 20, 2015 and the sworn videotaped statement he gave two days later which detailed the events leading up to the drug-fuelled night of the murder and included graphic details about the slaying.

Wylie had been bound to a chair, his face covered in plastic wrap, and had been beaten and stabbed with multiple objects including a broken mirror, a box cutter, a curtain rod, screwdrivers, and a dagger with a skull and crossbones on it, the trial heard.

The statements provided the jury with a glimpse of the twisted relationship between the four young people — Wylie, Morningstar, Noel and Shephard — with Shephard at the centre of competing affections.

Testified in her own defence

Marissa Shephard, pictured here with her father Dave Shephard in May 2015, at her grandfather's funeral, was arrested on a Canada-wide warrant at a Moncton motel in March 2016 and has remained in custody ever since. (Facebook/Dave Shephard)

Shephard testified she didn't participate in the murder of Wylie, whom she described as a childhood friend.

She said she was either out working as an escort or was in another room when he was stabbed. After she saw him wounded and dying, she was too afraid to call anyone for help, she said.

Her defence lawyer, Gilles Lemieux, argued she had no motive to kill Wylie.

The Crown called 40 witnesses, including police officers and experts who described the crime scene and evidence collected.

The judge completed his eight hours of instructions to the jury on Monday night and deliberations began on Tuesday morning. The jurors delivered their verdict four-and-a-half hours later, shortly after returning from a lunch break.