The lawyer representing Brian Laundrie's family has filed a motion to dismiss the lawsuit against them.
Earlier this month, Gabby Petito's parents and step-parents filed a lawsuit which alleged Brian's parents, Christopher and Roberta Laundrie, knew their son had killed Gabby.
The lawsuit contends Mr and Ms Laundrie concealed that their son had confessed to the murder from investigators and Petito’s parents while the search for Gabby Petito was ongoing.
“In doing so, Christopher Laundrie and Roberta Laundrie acted with malice or great indifference to the rights of (Gabby’s parents) Joseph Petito and Nicole Schmidt,” the lawsuit claims, adding that this conduct was “shocking, atrocious, and utterly intolerable in a civilised community.”
The Laundrie's lawyer, Steven Bertolino has called the suit "baseless" and "frivolous" and confirmed a motion to dismiss the lawsuit was filed in court.
He claims the Laundrie family was simply exercising their right to remain silent.
"The Laundries have exercised their constitutional right to refrain from speaking and have relied on counsel to speak for them," Mr Bertolino said in a statement to CBS News.
"This is not only common practice in our civilised society but it embodies the exercise of fundamental rights under the United States and Florida Constitutions.
"The Laundries' rights are inalienable and the Laundries can never be liable for exercising their legal rights in a permissible way."
Gabby's disappearance on a trip last year with Brian and the subsequent discovery of her slain body in a Wyoming national park made international news.
The spectacle continued when police launched a manhunt to find Brian, who went missing shortly after Gabby was reported missing.
The FBI concluded that Brian strangled Gabby — with whom he had previous domestic quarrels and violence — and that Laundrie fatally shot himself in the Carlton Reserve swamp after returning home alone.
The lawsuit is seeking at least $30,000 ($A39,960) in damages from the Laundrie family.
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