HALIFAX -- A Nova Scotia man convicted of killing his girlfriend while she was asleep in her bed is looking to have his conviction overturned.

Nicholas Butcher's case was before the Nova Scotia Court of Appeal Wednesday, where his lawyer argued for either a new trial, or a reduced period of parole ineligibility.

Butcher is serving a life sentence for second-degree murder in Renous, N.B.

He was sentenced to life in prison, with no chance of parole for 15 years, in connection with the death of Montreal-born yoga instructor Kristin Johnston.

Johnston was stabbed multiple times in March 2016 while she was asleep in her Purcell's Cove home.

During his trial, Butcher testified he awoke to someone attacking him and he stabbed them, not realizing it was Johnston.

Afterwards, he cut his hand off with a Mitre saw in an attempt to end his own life.

A copy of his 911 call was released during the trial.

"Your girlfriend is dead?" the dispatcher said. "I killed her and I tried to kill myself," Butcher said.

Wednesday, Butcher's lawyer argued three grounds for their appeal.

The first was that the trial judge erred in admitting hearsay statements.

The second is that he allowed evidence of bad character.

"That was the evidence that Mr. Butcher was struggling financially, that he was struggling to find a job, that he was overall kind of in a low mood," said Jonathan Hughes, Butcher's lawyer. "It was in our opinion that that offered a, I guess, a false impression to the jury that would potentially lead to some propensity reasoning on their behalf."     

The third, and final, ground of appeal is that the parole ineligibility period of 15 years is too long.

"If we're successful on the first two grounds of appeal, our ask to the court is that they grant a new trial," Hughes said. "If those two grounds are ultimately rejected and the third ground is successful, we're asking the court to reduce his parole ineligibility period to 12 years."

The Crown argued Johnston was asleep and defenceless when she was attacked.

"The fact that this was a domestic homicide combined with the fact that victim was at her most vulnerable when she was attacked, I think raises it above a 10-year minimum parole ineligibility," said Crown Attorney Glenn Hubbard.

The panel of three judges hearing Butcher's appeal has reserved its decision until a later date.