Gabby Petito's Parents Slam Brian Laundrie's on Dr. Phil

Brian Laundrie may be the sole person of interest in the Gabby Petito case — but it's his parents that faced a lot of ire on Tuesday's "Dr. Phil."

Gabby's mom and stepdad Nichole and Jim Schmidt, and dad and stepmom Joe and Tara Petito, as well as family attorney Richard Stafford, sat for an interview, in which they harshly criticized Chris and Roberta Laundrie's ongoing silence.

"It's infuriating," Nichole said, revealing that she doesn't even know for sure to this day if Brian even drove the van back to Florida, but pointed out: "The van had to get there somehow."

"The van got there, and whatever happened with his parents after that, I don't know," Joe added. "We can only speculate, we don't know," Gabby's mom said.

Her dad added: "I honestly don't know — and to be honest with you, they probably wouldn't tell the truth to begin with."

All four parents said they texted and called Brian's parents several times, but never once got an answer. "Nothing. No response. Voicemails," they said. Even when Joe informed them they were calling the police because they had no idea where the couple was — still nothing.

"A normal parent, when you text someone that you're gonna call the cops because you can't find your child — they would reply," Joe said. "No response, no nothing."

Nichole then revealed that she initially believed both Brian and Gabby were missing together, and was worried for both of them ... not learning Brian had returned home without her until police told her on the 11th of September.

"We actually didn't know that van was in Florida at the time when we contacted [Brian's mom]," Nichole said. "I was just worried I hadn't heard from her. I didn't know about the van 'til the 11th."

"We actually thought they were both missing at that point in time when we were calling them," Joe said. "I was worried about both of them," Nichole added.

The moment she knew it was "bad, bad news" was the night of the 11th, when she finally reported Gabby missing. "A detective came to my door and let me know the van was in Florida." she said.

Another dark omen, Stafford interjected, was the fact Brian "requested to speak to a lawyer, and wouldn't speak to the police department."

But Joe believes that wasn't even Brian's decision, turning the crosshairs back on the parents once again.

"To be honest, we don't even know if he did that. That's what the parents did," he said. "That's what they did; they had papers at the door, handed them to whoever knocked at the door: 'Talk to the attorney.'

"I mean, that's not how you parent," he added. "I'm a dad, I make my kids stand up for their decisions. If they make a mistake, I'll help you, I'll walk you through that path."

"But you're going to own up to your mistake, because that's what a parent does. Not what they're doing. I'm sorry."

"Anyone who lived in that house is a coward," he said. "They don’t know how to stand up for their actions."