Noise: what would you do?

Long story short: I’ve been living in the same apartment for nearly 2 years now. I love almost everything about this apartment. The almost is the biggest problem;

One of my neighbors, every single morning since I’ve lived here (including weekends)- come 2:54-3:18 a.m., the most ground shaking ‘thuds’ come from one of my shared walls.

It rattles my bed, it’s continuous during that time. I have racked my brain trying to figure out what the noise could be and justify what it might be coming from. I have tried to knock on both of my neighbors doors to inquire numerous times and neither of them ever answer the door. I have to this day never seen either of them, but I know they are there for certain.

My apartment walls are not thin. There has never been a time that I’ve heard a peep aside from this. But it’s really starting to affect my sleep detrimentally. I am not a light sleeper by any stretch of the imagination, but this noise genuinely sounds like gunshots it’s so loud. It’s frightening.

I haven’t wanted to waste the property managements time with a complaint, they are the sweetest people, and I know they wouldn’t hesitate to do something about it if they could, but maybe they can figure out where it’s coming from unlike I can.

(My husband works in law enforcement, he’s currently deployed, and no, I’m not wasting an officers time on a noise complaint)

Just curious, what would you do?