Brian Laundrie was seen slapping and hitting girlfriend Gabby Petito in the Utah town of Moab weeks before her disappearance.
Police released audio from a 911 call made by a Moab resident who saw the couple’s violent dispute there on 12 August.
Police pulled over the couple’s Ford Transit van soon after receiving the 911 call, but the incident was not deemed serious enough to press charges.
Audio of the call, first obtained by Fox News, portrays Mr Laundrie as the aggressor in the incident.
“I’m right on the corner of Main St by Moonflower… I’d like to report a domestic dispute,” the caller says in the 49 second audio recording.
“The gentleman was slapping the girl… they ran up and down the sidewalk, he proceeded to hit her and then they drove off.”
Last week, Moab police revealed they had been called to a violent argument between Ms Petito, 22, and her boyfriend Brian Laundrie as a nationwide search for the missing YouTuber was underway.
Police officers attending the incident said Ms Petito had tried to hit Mr Laundrie after she feared he might drive off without her, causing her boyfriend to try to restrain her.
The incident was not deemed serious enough to merit domestic violence charges, and police sent Mr Laundrie to a hotel for the night while Ms Petito stayed in the van.
Attending officer Daniel Robbins said the couple appeared to have been going through a “mental health crisis”, according to a police incident report obtained by The Independent.
The officer reported that the couple both suffer from a mental illness which caused them to argue more, and they had not been taking medication during their cross-country trip in a converted Ford Transit van.
“That time spent created emotional strain between them and increased the number of arguments,” Mr Robbins wrote.
Ms Petito’s remains were discovered in a Wyoming national park on Sunday.