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.