Mom flips off another driver while driving, guy makes passive threats.

[miami32]

So today the moms and I are out driving to pick up a new space heater. We are pulling into the shopping center and this guy in front of us all of a sudden comes to a halt, puts his car in reverse, and backs up to pull into a parking space. My mom flips out and gives him the finger as we drive by. The second we go by, this man guns his engine and follows us to our parking space. He pulls up as both my mom and I are getting out of her blazer and says "Hey, I waved to you to say thanks. Why did you have to go off and give me the finger?" Now he doesn't say this like he is really angry. I mean he seemed annoyed, but nothing I would consider threatening at the point. My mom just keeps walking and I follow her. Well as we are entering the store I see him turn his car around and head back to our blazer. So I tell the moms to go inside and I'm gonna see what the [censored] is going on. I run to our truck and he is writing down the tags and make and model. At least that is what I figure he is doing. I ask him what exactly he is doing and he tells me, "You guys don't know who you're [censored] with."

I then responded with a dude are you serious, this is a little old lady and your going to cause problems? He nodded. He then told me to have a nice day with a dickish smile and gave a crappy salute to me as he drove off.

Now the thing is, this man drove a honda civic red hatchback that had a bad exhaust, and ugly cheap looking black rims. If he was important I would imagine he drove a nicer car. I feel like if he was a criminal, we would have got into some sort of physical altercation.

I called the cops and they basically said the only thing we could do is file a threat report. I got his tag # as well just in case.

The strangest part about is at no point did he seemed really angry, just annoyed and bent on revenge.

What is my play?