ONE of the first police officers to arrive at the bloodied scene of the Lin family murders wiped away tears as he agreed he remains “affected” by the sight of the slain relatives.

Sergeant Lachlan Kirby, a former Eastwood detective who now works as a police prosecutor, told the Supreme Court trial of Robert Xie that the murdered newsagent Min Lin was initially the prime suspect in the killings, because it took several hours to discover his body under a doona.

Xie, 50, has pleaded not guilty to murdering Min, his brother-in-law, Min's wife Lilly, her sister Irene and Min and Lilly's two sons Henry, 12, and Terry, 9, in the early hours of July 18, 2009.

The Crown alleges Xie had three motives for murdering the family inside the bedrooms of their North Epping home, including a “clear sexual interest” in a young female relative.

Sergeant Kirby became visibly emotional and brushed away a tear as Xie's barrister Graham Turnbull SC asked whether “a picture remains in your memory of a very shocking scene.”

“Yes”, he said.

“You are still affected by what you saw?” Turnbull asked and referenced the discovery of “the two children” dead in their room.

“Yes”, Sgt Kirby replied.

Earlier the jury were shown the first of “graphic photographs” of the crime scene, with Justice Peter Johnson urging them to view the material “as calmly and dispassionately as you can.”

“This first photo you see is one of many you will see [in the expected four month trial],” Justice Johnson said.

The trial continues.