Is the neighbor that makes loud noises in his apartment a serial killer?

I live in an apartment complex. I noticed a guy who has made strange noises, he’s been hitting something or making loud noises in his apartment. He does this late at night, and he’s been doing this for weeks now. <br><br>The other day, I heard him make loud noises in his apartment, and then I saw the door open, and someone came out of the apartment, but I could hear the loud noises continuing. I don’t know if this is related, but I don’t want to take any chances. <br><br>My landlord told me he has a good relationship with him, so I think he is probably harmless. But I am scared. Should I call the police and ask them to do something about it?