LA CROSSE, Wis. -

The La Crosse Co. district attorney is asking a judge to throw out the appeal of the West Salem man convicted of killing his parents.

D.A. Tim Gruenke filed his response Friday to Eric Koula's appeal.

Koula was convicted of killing his parents, Dennis and Merna, in their Town of Barre home in May 2010. He was sentenced to life in prison without parole.

In mid-November, Koula's new attorneys filed a motion appealing the conviction. They claim the trial judge improperly disallowed some evidence and that jurors heard unclear instructions regarding testimony made outside the courtroom.

Gruenke disagrees. "We think the instructions the judge gave them were entirely proper and even if there was a problem with it, we think it's a pretty minor issue and didn't prejudice the defense. We also think the additional evidence wouldn't have changed the outcome," said Gruenke.

A La Crosse County judge set February 13th as the next hearing date for Eric Koula's appeal.

Gruenke says the process could take several months.