Suspicious Vehicle in Empty Parking Lot

[Seamus Harper]

I'm the common area property manager for a shopping center here in California (my family owns the gym located within the shopping center, gym is currently closed due to COVID, parking lot is empty).

I received a call from our landscapers about a man who was harassing them, telling them they can't be spraying weed control whilst people are in their cars with the windows down.

I've noted that this car/individual has been there for at least the past month during prior visits but didn't think much of it at the time. My landscapers tell me that he gets there early in the morning and leaves late afternoon, staying in his car the entire time.

I approached the individual today and he was very hostile. He at first refused to tell me what he was doing there and told me that it was the landscapers harassing him.

Finally, after about 10mins, he told me he was monitoring the entire area, not just the shopping center. He had a computer and radio set up in the car.

I was tempted to call the police and confirm but I figured I'd come here first and see if anyone has had any experience with something like this before. 

Thoughts?

[Matt M.]

Who owns the parking lot? I'd call the non-emergency line and let the police handle it.