I had a similar thing happen in the Adelaide Park lands. I was doing landscape photos and had not realised some the cities homeless were sleeping under the brush.
In a different section of the parks, about 15 of them caught up with me. Told me I was spying and taking their photos. They did not ask, they snatched my camera still attached to my neck and wrenched it about. They said they were going to smash it and then beat me up. No security anywhere here
I told them and I assured them I was taking landscape images and finally convinced them to take a look. They went through them all. Trees, rivers, waterfalls, no poeple at all. Then they said that I might have another memory card or hiding them in another way. I assured them I had not deleted them and turned out my pockets (I left my wallet in the car so I had nothing of value except my car keys and camera).
They even checked out the sequential photo numbers to see I had not quickly deleted any.
I finally convinced them I had not taken any photos and even told them, if they wish, I will leave the park, and I did.
I am not going back there, no matter how nice the park looks. It is a pity.