Now, he is still the subject of a nationwide search and is the sole person of interest in her murder.
Mom Nichole Schmidt and stepfather Jim Schmidt spoke candidly to "60 Minutes Australia" about the young man they thought Laundrie was -- and who they now believe him to be.
"He was very polite and quiet," Nichole Schmidt said.
ALSO READ | What Gabby Petito's death by strangulation could mean for Brian Laundrie's case
She said she never had a problem letting her younger children look up to and spend time with Laundrie.
"He'd draw them pictures and stuff," she said. "He would read books to my little one at night before bed. So he just seemed like a nice guy."
"They got to know him, and they liked him," Jim Schmidt added.
Nichole Schmidt thought about the kind of relationship she wanted her daughter to be in, but a fear that Laundrie would do anything other than take care of Gabby never crossed her mind.
"I worried," she said. "I told her to be careful, be safe, to be aware of your surroundings. Don't trust anybody. But I felt safe because she was with Brian, and I felt like she would be OK."
Her parents are now back in Long Island after bringing Gabby's ashes home from Wyoming, and they are demanding justice.
"I just want to get him in a cell for the rest of his life," Nichole Schmidt said.
RELATED | Gabby Petito timeline: Everything we know about her disappearance
Dad Joe Petito tweeted an image of the Wyoming mountains with the words, "Love you, and miss you."
Over the weekend, the Gabby Petito Foundation marked her legacy with its first fundraiser on Long Island in the hope of benefiting other missing people and women in abusive relationships.
The search for Laundrie continues, with his family's attorney saying in a statement that Gabby Petito's death at such a young age is a tragedy.
He reminded that Laundrie is only a person of interest, and they'll address the pending fraud charge against him.
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