THE Quirk family would never have known what happened to their child if one of her flatmates had not come forward, a jury has been told.
Defence barrister Peter Nolan told Brisbane Supreme Court Ms Quirk's family knew their daughter Amanda had drug, health and mental health issues but they would not have known her fate without his client, Rachel Narelle Smith, going to police.
Smith, 40, and Christopher James Swan, 39, have pleaded not guilty to murdering their flatmate, Amanda Quirk, at their Booval home on the eve of Easter 2010, pointing the finger at each other.
"The agony that a person must go through, not knowing what happened to their daughter or son," Mr Nolan said.
"Without Rachel, none of these people would know."
Swan told police he slapped Ms Quirk once, tied her up with duct tape, stole money from her account and dumped her body.
Defence barrister James Godbolt asked the jury to consider why his client would tell police he did all those things but deny he had otherwise assaulted her or contributed to her death.
"There is real support, when you look at that evidence, for the account that he gave being an accurate one," he said.
"He takes the body in a vehicle to a secluded location and tells lies about Amanda Quirk's whereabouts.
"That does not provide any proof that he assaulted her ... that he held any particular intent."
The jury is expected to begin deliberations tomorrow.