(Albert Lea, MN) -- An Albert Lea man convicted of killing his ex-girlfriend with a hammer wants his murder conviction thrown out. The lawyer for Chad Gulbertson asked a judge to vacate the conviction of first-degree murder while committing domestic abuse of ex-girlfriend Jody Morrow -- who suffered at least 18 blows to the head and three stab wounds to the neck. Gulbertson's attorney argued prosecutors did not show enough evidence that Gulbertson engaged in domestic abuse, but the state countered there were enough examples to make the charge credible. He was also convicted of second-degree murder. The judge has 90 days to issue a ruling.