An Alberta man who murdered his sleeping wife by hitting her on the head with a hammer and then put her body through a wood mulcher faced her family Friday.

Trevor Bobocel, 42, sat in a packed Edmonton courtroom, frequently bowing his head, as victim Roxanne Bigelow's relatives tearfully read out victim impact statements.

Bigelow's mother, Hellen, spoke of the "hurt, madness and loneliness" she has suffered as a result of her daughter being killed and the fact she and another daughter now have to raise the couple's five children.

"These five children have no mom and I have no daughter," she said. "I only ask why."

She also spoke of the horror of having to deal with the children's questions at their mother's funeral regarding what their father did after the "senseless" killing.

"Why is mommy in such a small box?" she recalled her grandson asking.

Bigelow's nephew Max Rosenkranz stared directly at Bobocel as he spoke of his heart breaking as he heard one of the victim's children say he was "scared" to be near his father and said the five children "did not deserve this."

Rosenkranz also spoke of having previously looked up to Bobocel, but said he is now "lost beyond repair."

Bobocel earlier pleaded guilty to second-degree murder and committing an indignity to a body in relation to the gruesome March 11, 2011, slaying in Wandering River, a hamlet about 87 km northwest of Lac La Biche, which is about 220 km northeast of Edmonton.

According to agreed facts, Bobocel and Bigelow, 43, had been married for about 15 years, but they were having marital problems and Bigelow was saving money to leave the relationship, something which Bobocel was aware of.

Sometime between 5:55 a.m. and 6:30 a.m., Bobocel left their bedroom, retrieved a ball-peen hammer from his pickup truck and then returned and struck Bigelow on the head with the hammer three times while she slept.

Bobocel then flipped the mattress to hide the blood, made the bed, wrapped Bigelow in the bedding and carried her to his pickup truck and placed her in the box.

Bobocel then drove about 40 minutes until coming to Ray Vincent's worksite about 7 a.m. He spotted Vincent doing paperwork in his pickup and asked if he could use his Komatsu mulcher to mulch an animal carcass.

Vincent then saw Bobocel take a wrapped bundle from the back of his pickup and place it under the mulcher blade. He then saw him go into the mulcher cab and proceed to operate the machine to mulch up the bundle.

However, the mulcher stalled when the blanket became tangled in the blade. Bobocel then got out of the mulcher cab, grabbed a chainsaw from his pickup and used it to cut the blanket away from the blade. He then told Vincent he was done and that he was going to wash his truck.

Vincent went into the mulcher cab and started to use the machine to clean the area, but noticed a human torso. He then called 911 and reported all he knew. DNA evidence from the scene confirmed the remains were Bigelow's.

Bobocel was located by police about 8:45 a.m. near Owl River. His truck was on fire and he was standing beside it. He was arrested for his wife's murder and he admitted doing it in a statement to police on March 14, 2011.

Crown prosecutor Jeff Rudiak argued Bobocel, a logger, should be sentenced to life in prison with no chance of parole until he has served between 15 and 18 years.

"This is the ultimate abuse of trust on so many levels," he said, calling it a crime of "extreme, brutal violence."

Rudiak noted only 60 per cent of Bigelow's remains were recovered and said police told him if the blanket had not stalled the mulcher, "there would have been nothing."

Defence lawyer Hart Spencer argued Bobocel should be eligible to apply for parole after serving 10 to 13 years.

Spencer said Bobocel is "apologetic, remorseful and certainly ashamed of his actions" and spoke of how he tearfully confessed to police his "spontaneous act."

Spencer also pointed out that, despite Bobocel being found fit to stand trial and not having any diagnosed mental illness that could have resulted in him being found not criminally responsible, two psychiatrists had opined he was suffering from a "delusional disorder of mixed type."

Spencer also told court Bobocel had said "he lost it and went into a bleeping rage" and that he had intended to kill himself, but failed to carry it out.

Bobocel declined an opportunity to speak in court.

A sentencing decision is scheduled for Sept. 12.