Grace Robotti admits she killed the mother of her great-grandchild by hitting her in the head 26 times with a small crowbar, but Tuesday she pleaded not guilty to the charge of second-degree murder.

鈥淒uring the course of evidence I want you to keep in mind two things,鈥� Robotti鈥檚 lawyer James Pennington told a jury of seven men and five women, as the long-awaited trial for the 65-year-old got underway in 91大黄鸭.

鈥淥ne, self defence 鈥� how it started and how it progressed. Also consider provocation.鈥�

In his opening statement Crown counsel John Swanson told the jury that Robotti and Roxanne Louie, 26, had a strained relationship due to differing opinions on the nutritional and developmental needs of Louie鈥檚 three-year-old son.

These differences reached a tragic peak Jan. 4, 2014 when Louie was killed during a fight while staying over at Robotti鈥檚 Penticton home. Her body was found in Naramata nearly a week later.

The two women鈥檚 lives became intertwined in 2011, when Louie dated Robotti鈥檚 grandson Dylan Spence. They had a child, but were only together until October of 2012 when a violent fight set them apart.

An acrimonious custody battle between the two followed and when Spence was granted visitation it was held at Robotti鈥檚 home because he worked in the Alberta tar sands.

The child even had his own bedroom at his great-grandmother鈥檚 and was visiting her in Penticton when trouble erupted.

Louie had moved to Vancouver from the South Okanagan earlier in 2014 and Robotti had traveled there a couple of weeks before Christmas to pick up the boy.

Swanson told the court Louie hadn鈥檛 firmed up plans herself to return to the South Okanagan for the holidays at that point.

Around Dec. 27, 2014, Louie decided she wanted to visit with family and made the trip to the Okanagan.

At some point while there, Louie went to Robotti鈥檚 to pick up the boy for a day of family tobogganing. Swanson told the court the he didn鈥檛 want to leave his great-grandmother鈥檚, so Louie stayed overnight instead. The next day Robotti bought the boy a snowsuit and drove them both to Louie鈥檚 for the snow day.

The boy eventually returned to Robotti鈥檚 and Louie went to stay with her father. After an argument with him, she opted to stay with Robotti.

鈥淩oxanne stayed with Robotti (from Dec. 30) to when she was killed by Grace Robotti,鈥� said Swanson. 鈥�(On Jan. 4, 2014) they got into a heated argument from around 2 a.m. to 2:30 a.m. about the child.鈥�

The child witnessed the conflict and was in the room crying. At some point Robotti鈥檚 brother Pier went to the home and helped calm the child.

As Pier put the child to sleep the argument raged on.

It started in one room, escalated to a physical fight and moved into another room with the women 鈥渉itting each other and pulling each other鈥檚 hair,鈥� Swanson told the jury.

鈥�(Louie) grabs a 10 inch, 14-ounce crowbar and swings it at Robotti,鈥� Swanson said. 鈥淭hey wrestle in the bedroom and fall on the floor.鈥�

Then, with the child asleep in another room, Pier went back and 鈥渟ees (Louie) on top of Robotti with a crowbar in hand,鈥� he said.

鈥淗e consequently pulls Louie off and throws her on the floor,鈥� said Swanson.

The effort to subdue Louie continued, but she didn鈥檛 stop fighting.

鈥淧ier Robotti positioned his body on top of Roxanne Louie鈥檚 and pinned her on the floor 鈥� he tried to control her hands and arms and get the crowbar,鈥� said Swanson.

鈥淚t fell to the floor then Grace Robotti started hitting Roxanne Louie in the head 鈥� she can鈥檛 fight back, Pier Robotti has her pinned.鈥�

Autopsy evidence indicates that Louie took at least 26 blows to the head and it could have taken from 15 minutes to three hours for her to die from the injuries incurred.

After she died, Swanson said Grace Robotti asked her brother to take the body from the home and started a 鈥渇everish effort鈥� to clean up so the child wouldn鈥檛 wake to see the carnage.

While she took Louie鈥檚 belongings and the crowbar to dumpsters around the area, Pier dumped Louie鈥檚 body down an embankment in Naramata where it was covered in a heavy snowfall.

Robotti then planted a story that Louie left of her own volition and she doesn鈥檛 know where she is. A missing person鈥檚 investigation got underway.

Crown counsel will call 17 witnesses over the trial that鈥檚 scheduled to carry on until April 14.