Gabby Petito's family sues Brian Laundrie's parents, alleging they knew Petito was dead while search was ongoing

The parents of Gabby Petito claim in a new Florida lawsuit that Brian Laundrie told his parents he had killed her before he returned home alone from their ill-fated western trip in a converted van.

The lawsuit filed Thursday in Sarasota County Circuit Court contends that Laundrie told his parents on Aug. 28 that he had killed Petito, 22, his fiancee of about a year at the time.

Petito's disappearance on the trip and the subsequent discovery of her slain body September 19 in a Wyoming national park became a national obsession, augmented by the later search for Laundrie in a Florida nature preserve.