The woman who helped raise 15-year-old Tina Fontaine says she is disappointed after learning Crown prosecutors will not appeal the case of the man acquitted in her death.

"I don't know how to really feel about it, but I just know it was just like getting slapped," said Thelma Favel, a great aunt who raised Fontaine for several years. "All I thought about was Tina. I guess she just didn't matter."

Last month, a jury found Raymond Cormier, 56, not guilty of second-degree murder in connection with the death of the Indigenous teen, whose 72-pound body was found wrapped in a duvet cover weighed down with rocks in the Red River in Winnipeg on Aug. 17, 2014.

Prosecutors said Tuesday they will not appeal.

"When a jury finds the accused person not guilty, the Crown can only appeal errors on questions of law," a Manitoba Justice spokesperson said in a statement.

Tina Fontaine, 15, was found dead in the Red River in August 2014 wrapped in a duvet cover that was weighed down by rocks. The cause of death remains a mystery.

"After a critical review of the law by the Manitoba Prosecution Service's appeal unit and the Crown attorneys who prosecuted the case, it has been determined there are no grounds to base a successful appeal."

Fontaine's death added pressure to calls for a national inquiry into missing and murdered Indigenous women and girls, which is now underway.

The cause of her death remains a mystery.

Calls for justice

Critics pointed to the verdict as an example of how Canada's justice system fails Indigenous people, and there were several marches across the country after Cormier was set free.

Sheila North, grand chief of Manitoba Keewatinowi Okimakanak, said that there won't be an appeal further underscores the need for change.

Marchers hold up signs that read 'Love for Tina' and 'Restorative Justice Now!' as they approach The Forks during a march in honour of Fontaine Feb. 23. The Canadian Museum for Human Rights is seen in the background. (Jeff Stapleton/CBC)

"It's just another blow to the family and another reminder that the justice system failed Tina Fontaine," North said.

"We're going to keep calling for a better justice system that has an Indigenous lens and perspectives in it and we're going to continue to hope that someday we'll find answers to what happened to Tina and thousands of others like her."

Observers in and outside the Indigenous community continue to call for justice reforms based on the outcomes of the Cormier trial and Gerald Stanley case.

Stanley was acquitted of second-degree murder weeks prior in the shooting death of Red Pheasant Cree Nation member Colton Boushie, 22.

Crown prosecutors announced last Wednesday they would not pursue an appeal, citing similar reasons.

No DNA evidence

During Cormier's trial, a jury of seven women and four men heard evidence from Crown prosecutors Jim Ross and Bretta Passler over a period of nearly three weeks. They reached a not-guilty verdict on Feb. 22.

Loud gasps filled the room as the nearly 100 reporters, police, politicians, Indigenous leaders, members of Fontaine's family and supporters in the court house listened to the verdict.

Southern Chiefs Organization Grand Chief Jerry Daniels, left, Assembly of Manitoba Chiefs Grand Chief Arlen Dumas, and MKO Grand Chief Sheila North speak to the media outside the courthouse after a jury found Raymond Cormier not guilty of second-degree murder in the death of Fontaine. (Brett Purdy/CBC)

The case was largely based on circumstantial details. No DNA evidence was found linking Cormier to Fontaine's death.

"This is not a case that can be proven or disproven by forensic evidence," Ross told the jury during his opening statement on Jan. 29.

'Never want Tina forgotten'

Favel, who raised Fontaine for years on Sagkeeng First Nation, broke down in tears as people filed out of the court the day the verdict was handed down.

On Tuesday, she said she was not holding up well after Crown prosecutors told her they won't pursue an appeal.

"It hurt, it hurt really bad," she said. "Like, Tina doesn't even matter to anybody, to the justice system."

Favel said she doesn't know where to go from here but maintains something more must be done.

"I'm going to keep fighting for justice for Tina. We're not done yet," she said.

"I'm not giving up with this.… I never want her name forgotten, I never want Tina forgotten."