Gabby Petito's parents have opened up about her relationship with Brian Laundrie and her tragic murder in a new documentary coming to Peacock this week.

The Sun reported that "The Murder of Gabby Petito: Truth, Lies and Social Media" will be available to stream on Peacock beginning December 17.

According to Peacock, the documentary will give insight into Petito's story, the unanswered questions about her disappearance and death, and "the shocking conclusion."

In the new documentary trailer, the Petito family, including her mom Nichole Schmidt; her dad, Joe Petito; her stepfather, Jim Schmidt; and her stepmother, Tara Petito, all speak out about how they felt about Petito's disappearance and death.

"It was like every parents' nightmare. Just like, in a flash of second. She's gone, she's missing," Jim Schmidt said in the trailer.

Nichole Schmidt noted that the thoughts going through her head were "something really bad has happened to her." "It's still unbelievable. I don't understand it." 

Joseph and Tara Petito described the time that their daughter was missing as "horrific" and "a blur."

"Her (Gabby Petito) bright, beautiful light touched a lot of people," Tara said in the trailer of the family's first documentary interview.

Gabby Petito disappeared on a cross-country road trip with Brian Laundrie. The couple was traveling to Oregon when Petito stopped communicating with her family in Wyoming in late August.

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Gabby Petito's Parents Said Brian Laundrie's 'Quiet and Polite' Appearance Deceived Them

In an interview with the Australian television newsmagazine show "60 Minutes" in October, Gabby Petito's parents said that Brian Laundrie's "quiet and polite" appearance had deceived them.

Petito's mom said Laundrie "seemed like a nice guy," and thought he would take care of her daughter.

"He's [Laundrie] very polite and quiet," Nichole Schmidt noted, adding that Laundrie would even read books to "her little one at night."

Jim Schmidt added that every time Laundrie would come over, he was polite and talked to their other children, who also liked him.

When Petito embarked on a cross-country road trip with Laundrie, Petito's mom said she reminded her daughter to be careful, be aware of her surroundings, and told her not to trust anybody.

Although she was worried, Nichole Schmidt admitted that she still felt safe because Petito was with Laundrie.

"I felt like she [Gabby Petito] would be OK... I thought he [Brian Laundrie] would take care of her," she said.

Joe Petito said her daughter did look happy but noted that "as we look more and more into this, it might not have been as great as people online perceived."

Gabby Petito and Brian Laundrie's Death

Brian Laundrie was named a person of interest by the North Port police after returning home alone on September 1 or 10 days before Gabby Petito was reported missing by her family.

Petito's body was found at the Spread Creek Dispersed Campground near Grand Teton National Park in Wyoming on September 19.

A Teton County, Wyoming coroner said she was strangled to death by a "human being," and the manner of death was homicide. 

After a month-long manhunt, the North Port police and the FBI agents found Laundrie's remains in a swampy area of Myakkahatchee Creek Environmental Park on October 20. 

The partial skeletal remains were confirmed to belong to him after a review of dental records. According to the autopsy report, Laundrie died of a gunshot wound to the head, and the manner of death was suicide.

Brian Laundrie was never charged in connection with Gabby Petito's murder. But an arrest warrant was issued for him for allegedly using Petito's debit card after her death.

READ MORE: With Brian Laundrie Dead, Gabby Petito's Parents Find Their Justice by Helping Others, Launch New Twitter Page to Help Find Missing Persons

This article is owned by Latin Post.

Written by: Joshua Summers

WATCH: The Murder of Gabby Petito: Truth, Lies and Social Media - From Peacock