Video Shows Gabby Petito's Van Door Closing 3 Days After Last Sighting

Enhanced video footage of Gabby Petito's van, purportedly filmed after her last known sighting, has surfaced online appearing to show the back door of the vehicle being closed as another car approaches.

The chilling moment was spotted by Brent Shavnore, a U.S. Marine Corps veteran turned videographer, who noticed the movement on a video first posted to YouTube by Jenn and Kyle Bethune.

The Bethunes captured the encounter on their dashcam while traveling cross-country in an RV.

They say the footage was recorded in Spread Creek Dispersed Camping land in Grand Teton National Park, Wyoming, on August 27, three days after the 22-year-old's last official sighting.

While the original version of the video picked up no movement in or around the van, Shavnore was able to further enhance the footage.

Posting the resulting video on Twitter, he noted "you can clearly see the back door of their van abruptly close."

The enhanced footage, which Newsweek has independently verified, has been viewed more than 268,000 times on Twitter.

Shavnore told Newsweek: "I was watching the YouTube Video released by Red White and Bethune looking for movement in the van. The van is easy to shake if someone is inside and moves it.

"When zooming in to enhance the video on my editing software I noticed a black line splitting the center of the doors making it clear to me that the right rear passenger door was open."

He says he was left shaken by what he saw.

"To be completely honest, when I saw that door close, it sent a harrowing chill down my spine," Shavnore says.

"By the time the video was done rendering my fingers were shaking so bad It was difficult to type the words on my Twitter post. I've edited emotional videos before, this one was by far the most difficult, not from a technical perspective, but from an emotional one."

The enhanced video footage has come to light a day after the FBI announced that human remains had been discovered in the Spread Creek area of Wyoming which are "consistent" with Petito.

Despite the discovery, the authorities have yet to confirm the veracity of the original YouTube video.

The van in the clip matches the description of Petito's car while the couple says the vehicle had "Florida plates."

Investigators previously confirmed to Newsweek that police have yet to verify whether this is the van used by the couple.

However, a statement posted to the Find Gabby Facebook page, said that her family is aware of the footage and, crucially, "believe this is the van for multiple reasons."

Petito is understood to have visited several national parks in Colorado, Utah and Wyoming with her fiancé Brian Laundrie.

She was last seen checking out of a hotel on August 24 and was most recently active on social media on August 26 when she posted a picture to her Instagram account.

Laundrie, 23, returned home to North Port, Florida, with the van, on his own on September 1. Petito's family reported her missing 10 days later. He initially refused to speak to investigators about his fianceé's disappearance.

Laundrie had been staying at his parent's home but has not been seen by his family since Tuesday. A major search is now underway.