Neighbors are suspicious, how best to approach

Title. I’ve recently moved into an apartment complex in a really lax area and neighborhood. My neighbors upstairs moved in about 4 weeks after I did.

Since then I’ve had interactions with them that could only be seen as negative. For starters it’s a non smoking community, explicitly stated in our lease, you sign a 4 page document—their 2nd day here they baked their place out with pot so much it made my living room reek. I told them about this and they moved outdoors (even though the property still says to not smoke). From time to time I get whiffs of pot, but nothing that is as bad as that first time

I ended up contacting our community front desk when I also noticed above me they had a propane tank with a grill, which is totally prohibited in our apartment complex. I mentioned they’re smokers too. I don’t have issues with these people, but within a few weeks of their arrival they blatantly broke 2 rules that are explicitly stated within our lease. For the record it took multiple contacts to the front for them to do something about the propane, and still nothing—pretty sure they’re just housing it in their unit right now.

Now today as I was getting ready to head out and walking upstairs (im in the sub level) a package that was delivered to the wrong building for me was torn open and cast aside at the building entrance. There are 5 units downstairs in the sub level and 5 above where the entrance leads directly to.

I walked over and found the unit in the Amazon photo of where the package was mistakenly left, and asked that owner, who said they brought it to our building side and left at the entrance corridor area. That means someone passed by it, ripped open the package, left the packaging outside and took the contents.

These contents were pet related, and I know outright on my side of the building only 3 people have pets. One set of neighbors I’m cool with on the sub level, the other set I’ve never met, and the last set the people this post is about that live in the entrance area.

Regardless if it was them or not, some piece of garbage stole my items and left the package out for me/whoever to find it.

I could be reading into this all, being paranoid and assuming it’s these people. I have a theory when I reported them to the front desk and they received warnings, they have it out for me. I tried to knock on their door today knowing very well they’re home just to ask if they happened to see a package, not even trying to accuse but having a suspicion, and no response.

I know I can’t go around accusing anyone, but I genuinely can’t help but have a hunch it’s them. And nonetheless, our community is small and out of the way of major locations that there’s not a chance someone random did this.

How would anyone handle shady and suspicious neighbors like this moving forward? Should I contact the front desk about a package being stolen? I don’t want to be a Karen neighbor, but after all this what am I supposed to do?