They are accused of purposely withholding information about Gabby Petito’s murder.
Lawyers for Gabby Petito and Brian Laundrie went face-to-face in court for the first time on Wednesday.
A judge is now to determine if their case will proceed to a jury trial next year.
In their lawsuit, Joe Petito and Nichole Schmidt claim Chris and Roberta Laundrie knew their son killed Gabby before she was reported missing and did not do anything about it.
They also accuse the Laundries of planning to help Brian flee the country and are seeking damages for the “intentional infliction of emotional distress”.
The Laundrie’s attorney described the allegations as “baseless” and sought to have the case dismissed.
The filing, obtained by PEOPLE, reads: “Christopher Laundrie and Roberta Laundrie exhibited extreme and outrageous conduct which constitutes behaviour, under the circumstances, which goes beyond all possible bounds of decency and is regarded as shocking, atrocious, and utterly intolerable in a civilised community.”
Mr Petito and Ms Schmidt were present in the court room on Wednesday, but the Laundries were absent.
Their attorney said this was “typical in a motion to dismiss”.
The judge is expected to rule on the motion in the next few days.
Last year, Gabby had been on a cross-country road trip with her fiancé, Brian, when she stopped responding to messages from friends and family.
It was soon revealed that Brian had abandoned the trip early and returned to his parents’ house in Florida, without Gabby. The Laundries did not tell Gabby’s family that he had returned early without her.
In September 2021, Gabby’s body was found in a national park in Wyoming. Medical examiners determined the cause of death to be strangulation.
Around this time, Brian vanished amid calls for his arrest. He was found dead in October.
After an intense investigation, Brian was found guilty of her murder after FBI discovered a written confession in a notebook belonging to him.
