The grandson of a 74-year-old woman accused of murdering her husband of 50 years testified during her trial Tuesday. Brian Semenovich described to the court how he once witnessed his grandfather chasing his grandmother with a kitchen knife with the intent to kill her.

Anne Semenovich, 74, is charged with first-degree murder and interfering with human remains. Alex Semenovich's remains were found in an incinerator on the family's property by a maintenance worker in April of 2008.

Semenovich's then 49-year-old daughter Laurie Semenovich and then 22-year-old grandson Brian Semenovich have been charged with accessory after the fact, and interference with human remains.

Brian Semenovich testified that his grandfather once chased his grandmother with a kitchen knife.

"He had a large kitchen knife in his hand...he was chasing her around the kitchen stove with this knife and his intentions were to kill her," the man testified.

He told the court that his grandfather had become increasingly hostile towards the family as he aged.

"He would snap immediately. He would let things build up before he would blow up."

Brian said in January of 2008, he gave his grandmother a loaded shotgun.

"My grandfather's hostility and violence was becoming more of an issue... I told her to use it as defence if he came at her when I wasn't around."

The 25-year-old said he was so concerned with the level of violence that he went to the RCMP on two separate occasions. Police told him it was a domestic issue and that he would need a statement from those involved. He explained that his grandmother was too afraid to complain to police and a report was never filed.

Brian also testified that his grandfather's mental health had deteriorated and he would often witness the 77-year-old talking to himself.

Earlier in the day, a forensic investigator walked the jury through physical evidence found on Semenovich's acreage near Spruce Grove, including photos showing a bloody bedroom where the 77-year-old victim was allegedly shot and killed.

The testimony comes a day after the court heard from a maintenance worker who testified about the day he and his co-worker discovered the remains of 77-year-old Alex Semenovich in an incinerator.

Vic Small with CJS Combustion Products told the court he had a conversation with the accused during an initial consultation in the fall of 2007 when Semenovich said she needed the incinerator fixed after buying it at a scrap yard.

"She shows me the unit itself and I say 'what would you want an incinerator like this on an acreage for?' It doesn't make sense. And she said 'I'd like to burn my husband in there.'"

Then months later, Small said he had been called to the woman's property to inspect why the incinerator wasn't working.

He went on to tell the court that when he and his co-worker Derek Lester opened the door of the incinerator, they thought there was a pig stuffed inside.

"He [Derek] said 'oh my God those aren't pigs' feet they're human,'" said Small.

"I just said 'drop everything and let's get out of here'...I was thinking we could be next. Just dropped everything and got out of there."

"We phoned the RCMP in Stony Plain right away," he added.

In an opening address Monday morning, Crown prosecutor Karen Thorsrud alleged that Anne went outside and, "Climbed on a ledge, opened the window, pointed the shotgun at her sleeping husband, pulled the trigger and killed him."

"This was a planned and deliberate murder," added the Crown.

The Crown also said Semenovich dragged her husband's body to the incinerator with the help of her daughter and grandson.

Semenovich has denied shooting her husband and claims she doesn't know how he died. But the 74-year-old has admitted to dragging her husband's body to the incinerator.

Monday's testimony followed a week-long fitness trial where the jury found Semenovich mentally fit to stand trial.

During that proceeding, Semenovich described what she called a horrible marriage filled with physical abuse.

Semenovich's trial is expected to last two weeks. Semenovich's daughter is also expected to take the stand at some point during the trial.

With files from Scott Roberts