Warning: This story contains disturbing content.

The mother of two little girls found dead on Christmas Day 2017 in Victoria has now testified about the last times she ever saw her daughters alive.

Sarah Cotton took the stand at the jury trial of her former common-law partner, Andrew Berry, who is charged with second-degree murder in the deaths of their children, six-year-old Chloe and four-year-old Aubrey. Berry has pleaded not guilty.

The bodies of Chloe and Aubrey were found in their beds in their father’s apartment, still in their pajamas. The Crown told the court the little girls had suffered multiple stab wounds.

Berry was discovered injured in the bathtub and was taken to hospital.

Cotton testified by December 2017, her communications with her ex were "kept to a minimum." She told the court in the weeks before Christmas Berry was "asking to get out of his parenting time," which she found unusual.

Cotton testified her birthday was on Dec, 21, and though Berry was supposed to have the girls by 5 p.m. that day, he emailed her and offered to let her keep them overnight. She told the court she replied, thanking him for the offer, but letting him know she had plans and would stick to the schedule.

She testified when she drove the girls to his place, she noticed the lights were off and remarked that it didn’t look like he was home. She testified Chloe told her he was there and added: “"We use flashlights. It’s just like camping." Cotton testified it made her think his hydro was shut off, and later said she asked the girls if they were cold there, but they said no.

Cotton testified she drove the girls back to Berry’s apartment after delivering presents to friends. She told the court she saw him smoking out back, and he approached them. She testified she gave him a gift composed of socks and school pictures of the girls, and didn’t ask about the hydro right at that moment.

"I didn’t want to provoke him in front of the girls," she testified, and added she wanted to keep the peace because it was Christmas.

"I was concerned for their well-being," she testified. "I thought I could work it out with him and get them back."

Cotton told the court she emailed Berry about her concerns regarding the hydro, but never got a response.

Cotton testified the last time she ever saw her daughters alive was the next day, Dec. 22. She told the court she returned to Berry’s building to drop off a stuffed animal for Chloe. She testified the girls met her in the lobby.

"They were so happy," Cotton testified, and added they asked her how many nights until they would see her again.

She told the court she hugged both girls and told them she loved them. She testified she told Berry to check his email, and he seemed "very distant, very far away."

Cotton testified the girls were supposed to be returned at noon Christmas Day, but that didn’t happen. She told the court she texted and called Berry but got no answer, and was in tears when his parents came over at 2 p.m., saying: "They’re not back yet."

Cotton testified she and Berry’s mother went by his building, where she knocked at the windows and buzzed at the front door. She told the court she didn’t hear any sounds from inside, or see any light coming from the suite.

Cotton told the court she and Berry’s mother checked a nearby rec centre, park and beach, but there was no sign of the girls. She told the court just before 2:30 p.m. she texted Berry to tell him she was going to the police.

It was later at the police station Cotton testified she was taken into the chief’s office and held tightly by two officers, who told her Chloe and Aubrey had been injured, and that they were dead. Cotton told the court she screamed.

During cross-examination, defence lawyer Kevin McCullough asked Cotton about an email she sent to a friend in May 2017 referencing concerns someone may be after Berry due to gambling debts, and suggested Berry told her about those debts. Cotton responded: "He didn’t tell me that."

McCullough then went on to read a series of messages between Berry and Cotton from summer 2017, and suggested they were co-parenting and getting along well. At one point, Cotton replied: "In this context, he seems reasonable."

In the Crown’s opening statement in April, prosecutor Clare Jennings told the court Berry had animosity towards Cotton, and his own parents, and was also in a “negative financial position."

The defence has not yet presented its case. The proceedings are also being streamed live to a Victoria courthouse for public viewing.

Cotton’s testimony is set to continue on Tuesday.

Follow the trial through tweets from CTV News Vancouver's Maria Weisgarber in court: