Xie trial: Son's death like 'stab in the heart'

"I just felt like the sky would collapse".

These were the words grandfather Yang Fei Lin has used to describe the moment he went to his son's Sydney home and saw it surrounded by police.

Mr Lin was giving evidence for a third day at his son-in-law Lian Bin "Robert" Xie's murder trial at the Supreme Court on Thursday.

Xie is accused of creeping into the home of his brother-in-law Min Lin and sister-in-law Lily Lin in North Epping in the early hours of July 18, 2009.

Once there, it is alleged he killed Min, Lily, her sister Irene and their two sons Henry, 12 and Terry, nine, with a hammer-like weapon.

He has pleaded not guilty.

Mr Lin cried as he was again asked to recall the events of July 18.

He said Xie had called him at around 9am that morning saying something like "Daddy, something huge has happened to brother Lin's family".

"I was really worried when I heard this. My wife was cleaning the dishes at the time. I said, `Stop cleaning the dishes, come downstairs'."

After Xie had picked them up and driven him and his wife to the son's home, Mr Lin said they arrived to a "terrible scene".

"The house was surrounded by police ... ambulance and police had set up a circle preventing us from entering. I felt that it must have been really, really serious and I just felt like the sky would collapse."

After discovering that his daughter-in-law, her sister and their two grandsons were dead, he said he felt very depressed.

However, their son's death hadn't been confirmed and he thought maybe he had been abducted.

When he was later taken to the hospital and told by a social worker that his son had also been found in the home, Mr Lin said he was "devastated".

"I just felt like I was being stabbed in the heart. I don't want to relive that moment," Mr Lin said with his head bowed.

Xie cried as he heard his father-in-law's evidence.

The trial continues.