The legal team for accused murderer Robert Xie say there is a “complete unlikelihood” that only one person was responsible for slaying the Lin family.

How did one man with no history of violence murder five family members?

That is the crucial question put forward by accused murderer’s Lian Bin “Robert” Xie’s defence.

The crown says the slightly built Xie was driven by bitterness when he crept into the his brother-in-law’s Epping home in Sydney’s northwest on July 18, 2009 and attacked the Lin family with a hammer-like weapon.

The battered bodies of newsagent Min Lin, 45, his wife Lily, 44, her sister Irene, 39, and their sons Henry, 12, and Terry, nine, were found later that day.

In his address to the jury at Xie’s Supreme Court trial on Monday, barrister Graham Turnbull SC asked his client, who maintains his innocence, to stand up.

While Xie stood in his blue-striped tie, white shirt and grey suit, Mr Turnbull told the jury to “look at him”, adding he was 177cm tall, weighed 60 kilograms and had no criminal convictions.

“There is no one to come forward to suggest he is capable of using this hammer-style weapon,” Mr Turnbull said.

Mr Turnbull then outlined a number of issues which are in dispute, including the crown’s assertion that the brutal murders were the work of one person and that they happened on the morning of July 18.

Rather, he said, there was a “complete unlikelihood that one person on their own, in the dark could have done what you are going to see was done”.

He argued that the police investigation was not one of who did it, but of showing “he did it”.

For three months in 2010, Mr Turnbull told the court that Xie and his wife Kathy were constantly watched by police with little to show.

Then, in May 2010, in a bid to “rattle Xie’s cage” and “provoke evidence”, Mr Turnbull said police told Kathy her husband was the killer.

They also incorrectly told her the shoe prints inside the home matched a size 9.5.

Xie was later filmed cutting up shoe boxes and flushing them down the toilet.

This, Mr Turnbull argued was all police got from the months of surveillance that also recorded two people who were “increasingly fearful” they were going to be “framed”.

Earlier on Monday, crown prosecutor Mark Tedeschi QC said that after Xie was charged with the murders in 2010 and taken to Long Bay prison he befriended a fellow inmate – known only as Witness A.

It is alleged Xie spoke to the inmate about buying a hammer from a two-dollar store and about planting DNA evidence on the body of a dead man.

But Mr Turnbull said Witness A was a person with a long criminal history who was substantiality rewarded for assisting police.

Of all the recorded conversations, all the crown was left with is inferences, he submitted.

“Robert Xie never told Witness A that he did it. Not once.”

Mr Turnbull also said Min Lin’s finances were in dispute, adding that there was a question as to whether the newsagent was able to legitimately make the money to underpin his assets.

The trial continues.

AAP lcf/tdw/sc/arb/pmu