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FIRST ON FOX: The parents of Gabby Petito added attorney Steven Bertolino to a civil lawsuit against Brian Laundrie's parents on Tuesday, alleging that it was "insensitive, cold-hearted and outrageous" for Bertolino to express the Laundrie family's "hope" that authorities would find Gabby's remains in September 2021. 

Joseph Petito and Nichole Schmidt, Gabby's parents, originally filed the lawsuit against Christopher and Roberta Laundrie earlier this year, accusing the couple of knowing that their son murdered Gabby and being aware of the location of her remains but refusing to speak.

"When they did choose to speak, it was through statements issued by Steven Bertolino, including a statement on September 14, 2021 that it was the 'hope' of the Laundrie family ‘that the search for Miss Petito is successful and that Miss Petito is reunited with her family,’" Gabby's parents said in a statement on Tuesday.

"It is believed that at the time the September 14, 2021 statement was issued, the Laundries and Steven Bertolino knew that Gabby Petito was deceased, and that under those circumstances, the statement was insensitive, cold-hearted and outrageous."

Gabby Petito wrongful death suit Moab Police Department Utah

A press conference is held by Gabby Petito's family in Salt Lake City on Nov. 3, 2022. (Fox News Digital)

Gabby Petito wrongful death suit Moab Police Department Utah

A press conference is held by Gabby Petito's family in Salt Lake City on Nov. 3, 2022. (Fox News Digital)

Gabby and Brian were on a cross-country road trip in the summer of 2021 when she disappeared in late August. Brian returned to his family’s home in North Port, Florida, on Sept. 1, and Gabby’s parents reported her missing on Sept. 11.

GABBY PETITO AND BRIAN LAUNDRIE: BOMBSHELL VIDEO EMERGES SHOWING HOURS BEFORE MURDER

The lawsuit focuses on the statement that Bertolino released on the Laundries’ behalf on Sept. 14 as searches were taking place for Gabby. It also accuses the Laundries of going on a camping trip in early September despite knowing that Brian killed Gabby and being aware of the location of her remains.

BOdycam footage Screengrabs show Gabby and Brian

Brian Laundrie and Gabby Petito are pictured in Moab police bodycam footage during an Aug. 12, 2021, domestic violence stop that led to her family's wrongful death lawsuit against Moab. (Moab Police Department)

Gabby's body was found on Sept. 19, and a medical examiner ruled that her death was a homicide by manual strangulation and blunt-force trauma to the head and neck.

Brian left his family's North Port home on Sept. 13 and went to Myakkahatchee Creek Environmental Park, where his remains were found on Oct. 20, 2021. He died of a self-inflicted gunshot wound.

GABBY PETITO HOMICIDE: TIMELINE OF DISAPPEARANCE WITH BRIAN LAUNDRIE

A note that was recovered near his body contained a confession.

"I ended her life," reads the note. "I thought it was merciful, that it is what she wanted, but I see now all the mistakes I made. I panicked. I was in shock."

Brian Laundrie note confession

Fox News Digital offered the first public glimpse of a confession Brian Laundrie left in a notebook in the Florida swamp where he killed himself last year. (Michael Ruiz/Fox News Digital)

Gabby Petito's family is suing the parents of Brian Laundrie and their lawyer, Steven Bertolino. (Steve Petito)

Bertolino did not immediately respond to a request for comment on Tuesday.

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The families of Gabby and Brian agreed to a $3 million settlement last month in the Petito family's wrongful death lawsuit against Brian's estate.

Gabby's family has also filed a $50 million wrongful death lawsuit against the Moab Police Department, alleging that officers failed to properly handle a 911 call after a witness claimed he saw Brian hitting Gabby and trying to steal her phone just weeks before her death. The lawsuit names the department, two officers who responded to the call and two former leaders.