The Calgary killer now twice found guilty of murdering a university student over hurt feelings at a house party is once again asking for his conviction to be overturned.

In June, Mitchell Harkes was sentenced to life in prison with no chance of parole for 12 years. It was the second conviction and second life sentence for Harkes.

He, along with a teenage girl, fatally stabbed Brett Wiese, a 20-year-old business student at the University of Calgary.

After the sentencing hearing, the Wiese family said they had had enough of the "never ending" and "gruelling" court process and had hoped it was over.

On Jan. 12, 2013, Wiese and his friends were hosting a house party.

Early in the evening, they told a group of underage girls to leave.

One of the girls returned with Harkes, angry and armed with knives. Wiese was killed and others were injured.

Harkes' first murder conviction was overturned after the Appeal Court found the trial judge had erred in instructions to the jury. A new trial was ordered and Harkes was again found guilty of second-degree murder.

Now, he's once again filed a notice of appeal asking for a new trial based on an argument the judge erred in his instructions to jurors ahead of deliberations.

No date has been set for appeal arguments.