Black reviewed security camera footage filmed outside his business and said he saw a woman defecating in the gutter about 8.30am on Sunday next to another vehicle, a white truck with a green stripe.
He believed there was no excuse for the act, as BP Southern in Cumberland St was open 24 hours and had a toilet.
Most of the faeces remained in the gutter this morning, he said.
When media approached the van yesterday, the freedom campers made a smoky getaway at full speed, about 50km/h.
Black doubted they would have got far and would still be in Dunedin today.
Police had not contacted him for the footage, he said.
Black said he believed the Dunedin City Council had issued the freedom campers a $200 fine for camping in an industrial area.