Hi Denise, thanks for the question.

We are unable to provide a precise identification for this insect. It is not a typical house fly but certainly related to it. It is either a Flesh Fly (Sarcophaga carnania) or a Stable Fly (Stomoxys calcitrans). Stable flies can inflict a rather painful bite to humans so be cautious in your interactions with it. I suspect that they are carry overs from the previous tenants of your apartment. A thorough cleaning of your apartment, especially kitchen and food storage areas, would be prudent. The Flesh Fly has distinctive red eyes, which I do not see in your pics. So I am more strongly inclined to this critter being a Stable Fly. Just vacuum them up as they appear and dispose of in the trash. If you wanted to be ultra-careful, consider have a professional exterminator inspect your apartment. Here is some more information about these two possible species:

https://bugguide.net/node/view/1066508

https://en.wikipedia.org/wiki/Stable_fly

Good Luck!!