The lawsuit named the police department and three of its officers: "Palmer," "Pratt" and Daniel Robbins. The suit also listed 10 other defendants but did not disclose their identities.
Gabby's parents and stepparents accuse the defendants of "negligent failure" in their investigation into an alleged assault between the vlogger and Brian that happened just weeks before her killing.
Body-cam footage showed a sobbing Gabby telling officers she hit Brian and that she suffered from OCD and anxiety. Moab police chalked the whole thing up to a mental-health crisis and not a domestic incident.
A second body-cam video was later released and told a slightly different story.
In the additional footage, Gabby told one officer that Brian hit her. Gabby's body was discovered in Spread Creek Dispersed Camping Area in Wyoming on September 19.
She had been strangled to death. The coroner revealed she likely died around August 27, just two weeks after the Moab police stopped Brian over the alleged domestic dispute and let him continue on his merry way.
As RadarOnline.com reported, cops ordered the couple to cool down for the night separately. Brian was put in a hotel room while she stayed in their van.
Gabby's family isn't just suing the defendants above over their daughter's death.
- Gabby Petito: Utah Cops Finally Lawyer Up in Family’s $50M Wrongful Death Suit as Two-year Anniversary of Murder Approaches
- Gabby Petito's Family Will Face Brian Laundrie's Parents Over Lawsuit, Judge Sets June Court Date
- No Civil Trial: Gabby Petito's Parents Reach Deal With Laundries as Killer Fiancé's 'Frantic' Voicemails Are Revealed
Joseph and Nicole have also taken legal action against Brian's parents, Christopher and Roberta Laundrie.
They accused Christopher and Roberta of knowing their son killed Gabby and withholding the information during the critical time in the grueling search.
They also alleged that a statement delivered by the Laundrie family's attorney on Christopher and Roberta's behalf gave them false hope that Gabby was still alive.
In documents obtained by RadarOnline.com, Joseph and Nicole want to know “each and every conversation” that the Laundries had with their daughter from the moment she started her cross-country road trip with Brian to the date her fiancé-turned-murderer returned home without her.
They also want “all emails,” “text messages,” “letters,” “notes, diaries, calendars, memoranda,” and “telephone calls or other forms of communication” between Brian and his parents during the road trip to when the medical examiner confirmed the confessed killer died from a self-inflicted gunshot wound to the head.
Brian confirmed he murdered Gabby in a notebook that was found near his body. He claimed it was a "merciful" killing.
Christopher and Roberta denied all of Joseph and Nicole's allegations.
Their response, filed in Sarasota County on July 15, comes on the heels of the judge's decision that Joseph and Nicole's suit will move forward to a jury trial sometime next year.