While investigators say they have no new information, police in North Port, Florida, where the couple lived with Laundrie's parents, have released video of an interview with Petito's father, Joe Petito.
"Positivity is hard," he said. "I'm trying to focus on the scenario I have in my head, that she's stuck somewhere and she just needs help. We've got to just go get her and bring her home. I know how these things sometimes end, and you know, I just try not to think of that."
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He said the family has traveled to Wyoming, because that's the last place Gabby was confirmed to be, and without help from the Laundrie family, they have no idea where else to look.
"It's the last known place that we have, and we're not getting a lot of information," he said. "We've got to start somewhere, and there's 2,500 miles between Wyoming and Florida. So if we start now, it's less we have to do when we pinpoint a better location. That's that's how we look at it. What if we get lucky, and we don't need Brian anymore? We find her right now, so she's good, we bring her home, she tell us what happened, and we move on."
As for what Gabby's father thinks of Brian Laundrie, he said he's focused elsewhere.
"Whatever I say here is not going to help me out there, so that'll be later on," he said. "I'll let the courts and society judge them. I've already did my judgment, it's not going to change. So now I'm focusing on what matters."
Still, he begged the Laundrie family to provide information and cooperate with authorities.
"I'd just like his parents to understand, parent to parent, this is a serious issue, and I wouldn't wish this on them," he said. "No matter what I'm going through right now, I still don't wish this on them because it's that horrible to deal with."
He called on the Laundrie's friends and relatives to press them for information.
"If you associate with the Laundries, call them, ask them, 'Hey listen, what do you know? What's going on? We want to find this girl too. What's your son doing? If he knows anything, he should be telling them,'" he said. "This type of behavior is just, it's cruel, it's heartless."
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He said Gabby brought light and hope into the world, and that her presence is needed.
"She's always trying to look at the brighter side of things," he said. "You can't fault someone for that. There's so much negativity in the world, and you turn to this beautiful soul, and she just sees the beauty in it. You don't see people like that a lot, and it's probably one of the reasons she's got so much attention. It's because people know that she sees the beauty in everyone and everything. And that's awesome."
He reiterated that the sole focus is bringing Gabby home, and all the other topics are secondary.
"Everything else with Brian, everything else with the Laundries, that doesn't matter until she's back," he said. "When she is back in our home, we can worry about that stuff then. Until then, there's one goal and one goal only: Bring Gabby home. It's that simple. This is not a difficult thing to realize."
North Port Police Public Information Officer Josh Taylor said authorities across the country, including the FBI, continue to follow every lead.
"I can confirm that law enforcement has touched based with a sister of Brian Laundrie," he said. "It is my understanding that nothing of substance has been shared. Brian has still not spoken to us."
Laundrie has been named a person of interest by police after he returned for Florida alone 10 days before Petito was reported missing by her family in Blue Point.
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Petito is described as a white female, approximately 5-foot-5 and 110 pounds.
She has blonde hair, blue eyes, and several tattoos, including one on her finger and one on her forearm that reads "Let it be."
Detectives are asking anyone with information on Petito's disappearance to contact Suffolk County police at 1-800-220-TIPS, the North Port Police Department at 941-429-7382, or the FBI at 1-800-CALL-FBI.
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