Man Heard Gabby Petito Ask Brian Laundrie 'Why Do You Have to Be So Mean?' During Dispute

A man who witnessed the Aug. 12 argument between Gabby Petito and fiancé Brian Laundrie in Moab, Utah, told police at the time that "something seemed off."

According to a recently released written statement, the witness, identified only as Chris, told Moab police he was outside the Moonflower Community Cooperative near Arches National Park when he saw the couple in the middle of "some sort of dispute," KSTU reports.

In his statement, Chris wrote the couple were "talking aggressively" and could have been "play fighting," but it was hard to tell because "something definitely didn't seem right," according to WABC.

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"It was as if this guy was trying to leave her, and maybe take her phone?" Chris wrote, adding that Gabby was punching Laundrie in the arm while trying to get back into the van in which they were traveling.

He noted when she made it back inside her vehicle, Gabby asked Laundrie, "Why do you have to be so mean?"

Another eyewitness called 911 to report the incident, telling the dispatcher Laundrie had been slapping Gabby.

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Body camera footage of officers responding to the domestic dispute report shows Gabby crying and ends with the couple being asked to spend the night apart, with Gabby keeping the van and Laundrie sent to a hotel.

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A U.S. park ranger who responded to the incident told the Deseret News she spoke with Gabby that day and had warned her that her relationship with Laundrie appeared to be a "toxic" one.

"I was probably more candid with her than I should've been," Melissa Hulls, a visitor and resource protection supervisor at Arches National Park in Utah, recalled of their interaction.

RELATED VIDEO: Body Found in Wyoming Confirmed to Be Missing 22-Year-Old Gabby Petito, Who Died by Homicide

"I was imploring with her to reevaluate the relationship, asking her if she was happy in the relationship with him, and basically saying this was an opportunity for her to find another path, to make a change in her life," Hulls said of Gabby, who was living with Laundrie and his parents in Florida prior to the trip.

"She had a lot of anxiety about being away from him, I honestly thought if anything was going to change it would be after they got home to Florida," Hulls added.

Gabby was reported missing on Sept. 11 — 10 days after Laundrie returned to his parents' home in the white van he and Gabby had used to travel across the country. Relatives last had contact with Gabby on Aug. 25, when she was near Grand Teton National Park in Jackson, Wyoming.

On Sunday, the FBI announced that human remains had been found in Grand Teton National Park that were "consistent with the description" of Gabby. Law enforcement officials confirmed on Tuesday that the remains belonged to Gabby and that she had died by homicide.

Once Gabby was reported missing, Laundrie was identified as a person of interest in the case and refused to sit down with investigators to discuss his fiancée's whereabouts. He has also since gone missing, with authorities in Florida currently conducting searches for him.

He has not been named a suspect at this time.

On Sept. 15, PEOPLE spoke with Gabby's father, Joseph Petito, who said his daughter was "amazing."

"She's so artistic. She's an amazing artist. She loves to draw," he said. "She has a great eye with decorating … She's that flower child type of personality. The old soul, you know?"

"If Woodstock was still going on, she'd still be there, man," Joseph added. "She's a hippie from the '60s, all right? She's a Beatles fan, round glasses … a free spirit."

If you have information on this case, call 1-­800-­CALL-­FBI (225­-5324).

If you are experiencing domestic violence, call the National Domestic Violence Hotline at 1-800-799-7233, or go to thehotline.org. All calls are toll-free and confidential. The hotline is available 24/7 in more than 170 languages.