Gabby Petito and Brian Laundrie are seen during their cross-country road trip.
CNN  — 

The parents of Gabby Petito have filed a motion to add Laundrie family attorney Steven Bertolino as a defendant in an ongoing civil lawsuit against Brian Laundrie’s parents, Christopher and Roberta Laundrie.

Petito, an aspiring travel influencer, vanished in the summer of 2021 on a cross-country road trip with Brian Laundrie. As a nationwide search ensued, attention also turned to Laundrie, who returned home to Florida and vanished in a nature reserve.

Days into the search for Laundrie, Petito’s body was found in Grand Teton National Forest in Wyoming, and a coroner ruled she died by strangulation. Laundrie’s body was found in mid-October 2021 in the Florida nature reserve, along with a notebook in which he claimed responsibility for her death. A medical examiner determined he died of a self-inflicted gunshot wound.

Joseph Petito and Nichole Schmidt filed the motion Tuesday in the 12th Judicial Circuit Court in Sarasota County, Florida, court documents show.

Petito and Schmidt first filed the lawsuit against Laundrie’s parents in March, alleging they knew their son Brian Laundrie murdered Gabby Petito and were working to help him flee the country.

The motion claims Bertolino – in addition to Laundrie’s parents – knew that Petito had been murdered and knew the location of her body when he issued a statement on behalf of Laundrie’s parents on September 14, 2021, about the search for Petito.

“It is our understanding that a search has been organized for Miss Petito in or near Grand Teton National Park in Wyoming. On behalf of the Laundrie family it is our hope that the search for Miss Petito is successful, and that Miss Petito is reunited with her family,” the Laundrie family said in the statement detailed in the motion to file a second amended complaint.

A week after the statement’s release, the Teton County coroner confirmed that human remains found in the Bridger-Teton National Forest were those of Petito.

The motion also claims it was “beyond outrageous” for the Laundries and Bertolino to “express their ‘hope’” that Petito be found when they already knew she had been murdered.

Bertolino, in a statement Wednesday to CNN, declined comment.

Last month, a Sarasota County judge ruled in favor of Gabby Petito’s family in a separate, wrongful-death, lawsuit against the estate of Brian Laundrie.