It is the crown's simple proposition that Robert Xie killed five members of his Sydney family, alone and in the dark.
But the defence says the crime scene evidence tells a different story.
In his closing address at the long-running trial, Xie's barrister Graham Turnbull SC, has reminded the jury "this man is in your charge".
"The decision you have to come to is whether or not the evidence is sufficient to convict him of five counts of murder."
Mr Turnbull said the crown case offers up a "simple proposition" - that "one person did this, in the dark and it is Robert Xie".
But Mr Turnbull said "facts from the crime scene we contend - and you might think with good reason - establish that it was not one person and it could not have been in the dark".
The crown argues Xie was filled with bitterness and hatred when he crept into the North Epping home of his brother in law Min Lin in the early hours of July 18, 2009.
Wielding a hammer, it is alleged he killed Min, Min's wife Lily, Lily's sister Irene and his nephews 11-year-old Henry and nine-year-old Terry.
Xie has pleaded not guilty.
In finishing the crown's closing submissions earlier on Tuesday, Mark Tedeschi QC pointed to a string of "remarkable features" of the case against Xie.
This included that there were no signs of forced entry at the home and that a blood stain found on Xie's garage floor matched the DNA of at least four of his alleged victims.
"It is remarkable that the two primary victims (Min and Lily) had their faces obliterated by the killer.
"And that for some time the accused bore considerable hostility towards Min," he added.
"We submit to you that the crown case has proven to beyond reasonable doubt that this accused, Robert Xie, murdered the five members of the Lin family," Mr Tedeschi said.
The closing submissions continue.
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