couple arguing while on the road. catie beck has the latest >> reporter: tonight the search of the swamp continues, a massive man hut for brian laundrie, now a person of interest in the homicide investigation of his fiance gabby petito. >> we are trying to cover every acre in this preserve. >> reporter: all 25,000 of them the vast area now a grid search by all-terrain vehicles, k-9s and dive teams so far, no sign of laudrie who headed there a week ago with a backpack, according to his parents. >> you can't keep chocolate in utah >> reporter: they had been documenting their trip since august laundrie returned without petito september 1st. her family reporting her missing ten days later >> what's going on >> reporter: newly released police report shedding more light on the couple's dispute while on the road gentleman was slapping the girl. >> reporter: a witness