As the search grows more desperate for Blue Point native Gabby Petito, her fiancé is remaining silent - despite pleas from her family to tell them her last known location.

"The family is devastated. Every day that this goes on, they get more and more desperate," says Richard Stafford, Petito/Schmidt family attorney.

The plea comes nearly a week after her mother reported her missing.

Meanwhile, fiancé Brian Laundrie, the last known person to see her, has not shared what he knows of her whereabouts to authorities.

“Two people went on a trip. One person returned. And that person isn't providing us any information,” says North Port Florida Police Chief Todd Garrison.

MORE: Live updates on the case of missing Blue Point native Gabby Petito

On July 2, Petito and Laundrie left Long Island to begin a cross-country road trip. Then on July 16, Petito documented her time at Zion National Park and on July 22, Petito and Laundrie were at Bryce Canyon National Park.

It was near Arches National Park in Utah that police say an incident took place. On Aug. 12, Moab Police Department were called to investigate a domestic problem involving Petito and Laundrie.

No charges were filed, and officers determined it was a mental health issue. But the video showed strain in the pair's relationship.

Less than two weeks later on Aug. 25, Gabby's mom Nichole Schmidt FaceTimed with her daughter from Wyoming.

Police say that was the last time Petito's mother saw and she believes heard from her. Petito's mom does not believe text messages sent after that date came from her daughter.

North Port Police in Florida say Laundrie returned home on Sept. 1 with Petito's van, but not Petito.

Detectives there are now calling him a person of interest in her missing persons case.

Joe Petito, Gabby’s dad, made a plea to the public during a news conference in Florida Thursday.   

"The only thing that matters is bringing Gabby home," said Petito. "I'm asking for help from everyone here. I'm asking for help from everyone from home. I'm asking for help from the parents of Brian. I'm asking for help from the family members and friends of the Laundrie family as well. There's a tip line that you can call anonymously. Whatever you can do to make sure my daughter comes home, I'm asking for that help."   

Multiple agencies in multiple states are pursuing every lead, including a possible link to a double homicide, in hopes it leads to Petito.

Those two people found dead were last seen in Moab on Aug. 13, near where the incident involving Petito and Laundrie occurred.