The grieving father of a young girl who was found dead in 2014 revealed Monday that he spent years worrying about his daughter's safety.

Four years after the body of eight-year-old Teagan Batstone was found in the back of a car in South Surrey, her mother is now on trial for second-degree murder.

"Certainly, reliving it is difficult, but to be honest, I relive it every day, right? Teagan is gone and she'll never be back," the victim's father, Gabe Batstone, told CTV News outside a New Westminster courtroom.

Earlier in the day, Gabe testified that he and Lisa shared custody of Teagan, with the child visiting her father, step-mother and brothers in Ottawa for portions of the year and having monthly visits with him in B.C.

He also testified that communication with Lisa had been challenging, acrimonious and at times combative, adding that the volume of messages from his ex-wife had increased in the months before their daughter's death.

"You deal with it because you keep the child's best interests, but we certainly were worried as we had been worried for years," he said.

Gabe told the court he had tried to get temporary custody of Teagan following a suicide attempt by Lisa in 2012, but the child was ultimately returned to her mother.

The Crown has stated it intends to prove Teagan was smothered, and that the killing was partly motivated by resentment towards the girl's father.

Lisa could be seen shaking her head several times throughout her ex-husband's testimony Monday and passing notes to her lawyers.

Gabe told the court he last saw his daughter alive while walking her to class on a Monday after spending time together the previous weekend.

"It was a day of just us and I do hold close to those moments and few memories," he told CTV.

He also testified that he got a message from Lisa on Dec. 10, 2014, the Teagan's body was found, saying their daughter had the flu and would not be going to school that day.

Lisa was arrested at the scene and charged less than 24 hours later.

In the three weeks since the long-awaited trial began, a forensics officer has testified about the items found in Lisa's car and home, including a note reading "I'm sorry" that was found in the kitchen garbage, and a plastic bag with duct tape around it.

With files from CTV Vancouver's Maria Weisgarber