It was likely to be a protracted investigation because the alleged thefts went back a decade and a large number of people had had access to the collection in that time.
The investigation was complicated by the fact the alleged thefts had only just come to light.
Asked whether the alleged thefts had been committed by an insider, Mr Robinson said that "on the face of it", that appeared to be the case. However, it was not necessarily so and police didn't have enough information to draw conclusions.
It is understood the society has had concerns for some time and commissioned a museum expert to prepare a report into the disappearance of the photos and the options open to museum officials. That report is thought to include lodging a complaint with police as one of the options. Legal advice to the society, however, was that they had no choice but to lay a complaint.
The museum held its quarterly general meeting on Saturday with a "photo collection investigation update" among agenda items. Members also planned to discuss a way forward for acquiring new photos.
The society didn't wish to comment when contacted last week, saying the matter was being dealt with in the proper way.
The museum has a substantial collection of photos, documents and artefacts in the former Far North District Council service centre on Kaeo's main road, previously housed across the road in the old post office.
Museum highlights include displays on the 1809 sinking of the Boyd and items from the Greenpeace flagship Rainbow Warrior, which was bombed in 1985 and sunk off nearby Matauri Bay. It also has displays on timber milling and missionary work from 1814 onwards.
