The trial of an Oak Bay father accused of murdering his two young daughters heard from the man's sister Thursday, including testimony about conversations she says they had immediately after the murders.

Andrew Berry has pleaded not guilty in the deaths of six-year-old Chloe and four-year-old Aubrey, who were found dead in Berry's Beach Drive apartment on Christmas Day 2017.

The jury heard Thursday that Berry's ex-partner, Sarah Cotton, had frantically texted his sister on Dec. 25, looking for her daughters.

Berry’s sister, whose identity is protected under a publication ban, said she texted Berry: "This will backfire on you Andrew if you hold the girls back from Sarah."

Berry's sister, who is an RCMP officer, sobbed in court as she recounted the moment two colleagues came to her door on Christmas Day to tell her that the girls were dead and her brother was injured. She said she "was a mess" and felt like she'd been "hit by a tidal wave."

She testified about meeting her parents at the Oak Bay police station after learning the news and worrying about how they would handle it.

"I felt this was going to kill them," she told the Vancouver courtroom.

She also described meeting her injured brother at Victoria General Hospital, where she said he sprung up from his bed when he saw her, and with "immense intensity" told her, "kill me."

She testified that she confirmed what she heard with a nurse and asked the nurse to document the statement.

"He looked so different," she said of Berry. "His hair was so crazy and his eyes… it was something I had never seen before."

Berry's sister also told the jury she bought a sweatshirt and sweatpants for him to wear when he left the hospital. On the inside of the sweatshirt's cuffs she wrote the words "I love you" and "truth."  

She went on to tell the jury she still loves Berry, regardless of what might have happened at his apartment that day.

"I don't know if Andrew killed his daughters or not," she told the court. "But I know he was there."

Cross-examination of Berry's sister began Thursday and is expected to continue through to Monday.