Gabby Petito, Brian Laundrie were involved in an incident at a Wyoming restaurant in late August

A couple from Louisiana who were vacationing in Jackson, Wyoming, last month said on Wednesday they saw an incident involving Gabby Petito and Brian Laundrie in a restaurant in one of the last sightings of Petito before her death.

Nina Angelo told reporters that she and her boyfriend, Matt England, saw a "commotion" as Petito and Laundrie were leaving The Merry Piglets Tex-Mex restaurant on August 27.

Angelo said Petito was in tears and Laundrie was visibly angry, going into and out of the restaurant several times, continuing to show anger toward the staff around the hostess stand.

The couples' waitress was also visibly shaken by the incident, according to Angelo. However, there was no violence or physical altercation between Petito and Laundrie.

The FBI is still to confirm about Petito and Laundrie's presence at The Merry Piglets.

Police in Florida said in a recent search warrant affidavit that Petito's mother received an odd text on August 27 and that it was the last communication from her. Petito, who was chronicling the couple's trip through national parks, also stopped posting to social media at that time.

Petito was first reported missing by her family on September 11 and her remains were found Sunday in Grand Teton National Park. The Teton County coroner in a preliminary autopsy determined the manner of death was homicide but has not disclosed the manner in which she died.

Laundrie, who arrived at his parents' home in North Port, Florida, three weeks ago, has not spoken to police about the case. His parents have told authorities they haven't seen him since last Tuesday.