That was a point I was trying to make upthread- you shouldn't need a warrant to allow LE to do a preliminary search of common areas of the building and to let them know if she had authorized access to the building for example. The parking garage, hallways, anybody who walks up and voluntarily lets you inside their apartments or wants to voluntarily talk to you. Of course you need a warrant to enter any private residences or areas presumed to be private but that preliminary search might have saved LE days or weeks by quickly identifying where to search and who to investigate. Range Rover not in the garage? OK lets quickly look at surrounding garages... There might even be evidence that is now lost as a result of the delay. The civil suit I expect on behalf of her son is for extending the mental anguish of not knowing what happened to your mother, fearing for your own safety from that uncertainty, possibly wrongful death if the building management did anything to contribute to her death (like a dangerous garbage chute, letting your buddy sell drugs inside who then kills someone, helping to conceal evidence, or if she was plausibly alive for days). People file for a whole lot less and we have only just started to see what the whole story looks like- the Ex- seems to be very savvy.
But IIRC, it wasn't LE asking the building for access to do a preliminary search, it was Heidi's friends and ex husband asking the building for access.