Just saw a man ABUSING HIS DOG. What do I do?

I heard a dog crying very loudly outside. I was wondering if a dog had gotten ran over by a car, I swear my instinct said don't go outside but I thought what if the dog is laying out there and needs help. So I looked outsisde and saw a man walking his dogs at the elementary school I live right across the street from, then he picks the dog up WITH THE LEASH AND STARTS SWINGING HIM AROUND WHILE CONTINUING TO WALK.

I'm a girl so I was not about to walk up to him, and also my STUPID *** IPHONE wouldn't let me take a video. I don't know what to do, where to go, or who to call about this.

Don't I have to have validity or proof of someone abusing their animals for them to do anything about it? Can I just lie about it so they at least check the dogs out for injury?

ANY ADVICE Please?!

Added (1). GOOD ADVICE EVERYONE! And I imeediately got in my car and saw that he lives right down the street from me.

Added (2). @Elizabeth he was swinging little dog around infront of him while continuing to walk as in the dog was off the ground, probably about 2 or 3 feet in the air.

Added (3). Thanks @kate I took your advice and the police are on their way to get a report on what I saw.

Call animal control or the police and report it. They don't need proof to investigate, and if you're willing to give an official statement, they can even prosecute based on it sometimes. If you don't know this man, though, they may have trouble locating him. Still worth reporting, though.

The school should have security cameras. Meaning call the police or SPCA and tell them your story. Make sure you state the name of the School so they can look into whether or not the school does have cameras. If the school does and it was all caught on film, they'll believe you.

RSCPA.
Call them or go to the police station give a description and his address
The police will go and see how the animal is being treated at home or they will hand the matter over to RSCPA
You need to do it immediately.

1. Swinging like swinging a little dog who is choked because he has a collar? Or swinging like pulling like he's trying to correct his dog?
2. Dogs show signs of abuse
3. I would call your local police department and report this.
4.It was a good thing you looked out to see what was going on instead of ignoring it.

Why did I get a thumbs down…

Call and report this now a Humane society or Animal control.

You can call the animal shelter or RSPCA and tell them when and where you saw this man do this. Keep an eye out for him again and next time take a photo or video or him to get an identification.