Less than a month after he was found guilty of first-degree murder in the death of a 13-year-old girl, Michael Briscoe has reportedly filed an appeal.

In early April, Briscoe was found guilty of first-degree murder, sexual assault and kidnapping after he was re-tried for his role in the gruesome killing of Nina Courtepatte.

In 2005, Courtepatte was lured from West Edmonton Mall, then sexually assaulted and killed in a rural golf course.

A month after Courtepatte's death, the body of Ellie May Meyer was found in a field in Strathcona County – officials determined she had died two days before the teen was slain.

Briscoe was the only person out of five to be acquitted of charges in the Courtepatte case in 2007.

He was re-tried on appeal, and the charges related to the death of Ellie May Meyer were added – Joseph Laboucan, who was also accused in both deaths, had already been found guilty in both cases.

Briscoe was found not guilty in Ellie May Meyer's death. He was given an automatic life sentence, with no chance of parole for 25 years.

CTV News has learned Briscoe is appealing both the first-degree murder conviction, and the sentence.

A decision has not been made as to whether the appeal will be heard.