The baby crying alone in the dark

I was sitting there at 10pm and I kept hearing a babie's cries outside my house. But I kept ignoring it thinking it could be anything for any number of reasons. It had been a while, but maybe not more than five minutes. When the crying never went away, I got my gun. You know the urban legends about crying babies on your doorstep. When I got halfway accross the lawn, I saw the dark shiloutte of a baby girl who's 2, across the street crying hysterically and banging her hands on the front door. The whole house was total darkness, except for a small glow coming from a downstairs window. I hid my gun, and quickly raced across the street, knowing she'd already been out there a while, by herself, in the dark, alone. When I hit the center divide of the road, the door opened a jar, and an arm from the darkness grabbed her and pulled her inside. The crying continued, and I heard some yelling in another language, and all the lights remained off. I went inside and thought about things. I have put my two year old in a room by himself to cry, but only for a few moments, to make him listen to me when I come back. This was different, and I don't think her parents were there. They own a restaurant and work a lot. The grandparents care for the baby frequently. But I don't know their routines, and the moms car wasn't there. Should I have called the local PD and had them do a welfare check? Or should I talk to the mom about what happened tomorrow? Or is this not my business at all? It wasn't too cold, my weather app is saying 54 degrees out. Thank you.