Idk why a random guy was filming me

I had something really unsettling happen tonight and I’m wondering if anyone else has experienced something similar or has any idea what the motivation could have been. My sister and I were leaving a Dollar Store just before closing. It was a holiday, so the parking lot was almost empty. We were already sitting in our parked car when a guy (probably around 21–25) in a black Nissan slowly drove in front of us with his windows down and very obviously pointed his phone at our car, recording us. Once he got past us, he sped out of the parking lot.
Instead of leaving, he drove into another completely empty parking lot across the street and sat there. We drove by because we thought maybe we knew him and it was some weird prank, but neither of us recognized him. As we drove past, he pointed his phone at us again and recorded us. We drove away and waited around the corner for a bit because we didn’t want to pass him again. A few seconds later, he started driving toward us very slowly and, again, had his phone pointed directly at our car. We left immediately, and it looked like he started turning around as we were leaving. There was no road rage or anything leading up to this. We didn’t cut him off, interact with him, or even see his car before this happened. We have no idea who he is. My family ended up calling the non-emergency police line, and an officer came out and took a report. Unfortunately, the video we managed to get doesn’t show his face or licence plate.
Has anyone experienced something like this before? Any idea why someone would repeatedly record two strangers like that? It was honestly really unsettling.