Domestic violence next door

Me and my family recently moved to a new apartment and our tenants are also renting a small garage/apartment to other people downstairs. 30 minutes ago a neighbor came to us and asked if we were renting this garage downstairs as well and we told him we weren’t and then he told us that earlier tonight he saw a man beating a woman in the garage and that he stopped it and the woman asked him not to call the police.

What should we do?? As I’m writing this I can hear them fighting when I go to the balcony and I’m on the third floor. I mean when you know that a woman is being beaten (and this is just the violence that has been seen) what can you do? Will the police do anything if we call them? Especially when she doesn’t want us to call the police (probably because she is scared).

So please help I don’t know what to do.