@Sid1701d9Ok. I haven't had an apartment as a crime scene ever so I guess it works a little different on those. If it's in the world then that's a different animal. So as I understand it, you have a sim in the detective career with an open case that was open when you shifted to another household to play. And that household happens to live in the same apartment or same building and you can still see the crime scene stuff. Have I got that right?
So, I don't mean to be Captain Obvious here, but it seems that the solution to get it cleaned up is to go back to the detective and finish the case and then go on to the next household. I have never stopped playing a household when there was a case open. I always finished the case before I switched. So this one is new to me.
But if that doesn't clean it up then you have stuff stuck in the world for like forever because you can't delete it in build mode. So the only thing I know of that might work is the T.O.O.L mod.
I agree with you that it should get cleaned up automatically when you travel out of the crime scene back to the Police Station so something isn't going the way it's supposed to. I've had it happen but was able to clean it up manually. Just never had anything left in the world. Everything was on a lot.