07/17/2015 03:13 EDT | Updated 07/17/2016 05:59 EDT

Loretta Saunders's killer Victoria Henneberry wants to appeal murder conviction

The woman who admitted to killing Loretta Saunders wants to appeal her conviction, saying she wasn't in the right mindset when she pleaded guilty to second-degree murder in April.

"I was distraught, under a great deal of stress and panicked. I'm not guilty of the charge of 2nd degree murder," writes Victoria Henneberry in court documents.

"My hopes are to have an appeal granted in order to have an overturned conviction or a fair and impartial trial."

Henneberry is currently serving a life sentence for Saunders's murder. She must serve 10 years before she can apply for parole. Her co-accused, 26-year-old Blake Leggette, pleaded guilty to first-degree murder and was also sentenced to life in prison.

Miriam Saunders, Loretta's mother, told CBC News she's outraged at the latest development. She says someone from the Victim Services Program called her family this week.

"The justice system, I'd like to say the F-word, but they're messing around with us big time. We thought all of this was over. I thought all of this was over. I was starting to heal," she said Friday.

"They keep bringing the pain fresh, as if I had just lost her. We have no one to turn to because this is the justice system who is doing it to us."

Saunders, a 26-year-old Inuk woman, disappeared just before Valentine's Day in 2014. Her body was discovered in the median of the Trans-Canada Highway, west of Salisbury, N.B., a couple of weeks later.

Court documents show she was murdered at her Halifax apartment over rent money.

Henneberry and Leggette were sentenced on April 29, and she had a 30-day window to file an appeal after the end of the trial. Henneberry said she was told the window was 60 days.

"I have since found that the information is incorrect or may have been misheard and/or misunderstood on my part," she writes. 

"After the sentencing I was quite overwhelmed by the ordeal but still had planned to appeal. My thoughts towards the appeal have not changed and I still aspire to follow through with the process."

Henneberry has not yet filed for appeal. The documents — filed in court and dated July 14 — are a request to extend the window in which she can file that appeal.

Henneberry will appear in court via teleconference on July 29.