Warning: This story contains graphic details.

It was an emotional day of testimony Thursday in the Andrew Berry murder trial.

The Oak Bay father is accused of killing his daughters, six-year-old Chloe and four-year-old Aubrey. Their bodies were found in his Beach Drive apartment on Christmas Day 2017.

Berry faces two second-degree murder charges and has pleaded not guilty.

On Thursday, the jury heard more testimony from Sgt. Michael Martin, the second officer to arrive at the gruesome scene.

He described entering Berry's darkened and cluttered apartment with his gun drawn, having been told there was "blood and carnage" at the scene.

The veteran officer became emotional on the stand, fighting back tears when describing the moment when he discovered the two lifeless little girls in their pyjamas in bed. He testified that he tried unsuccessfully to find their pulses and their bodies were cold.

Martin recounted how another officer arrived and also tried to find the girls' pulses. When asked on the stand, "Didn’t you already do that?" Martin choked up and responded, "I hoped I was wrong."

He described the other officer having to experience what he did, telling the court, "Sometimes you see things and you can't unsee them."

Martin told the court he was asked that night by a major crimes investigator why he had not arrested Berry. He said he responded that "preservation of life was paramount."

Berry's lawyer, Kevin McCullough, began his cross-examination of Martin on Thursday afternoon. That cross-examination is expected to continue Friday.

The trial is scheduled to last four months.