OH COME ON. You know what I'm getting at. You want to play silly games, fine: the body is found behind a dumpster at a grocery store (private property). Point is, someone has been murdered, and who it is & who did it is not immediately obvious to anyone.
In an anarchic government, it's in the grocery store's owner's selfish interests to just move the body from behind the dumpster to into it, and make the problem vanish. We could say noble things about the law of God being written on people's hearts and the inherent goodness in people and blather on about murder being bad for business, but fact is that dealing with a dead body by the dumpster is NOT in the manager's contract, and said body can easily be made to go away.
How often are people "found dead" in shopping malls?
You don't know, do you? Perhaps the seemingly low rate is because the brightly-lit, highly-monitored, carefully-watched-because-millions-of-$$$-in-business-is-happening location tends to deter shady behavior (such an environment cannot be extended everywhere). Perhaps it's because any "found dead"s are quickly and quietly taken care of.
But we dirgress.
Answer the question: a murder happens, and neither the victim nor perpetrator are immediately known - who notifies next of kin, and who apprehends the murderer?
Is this a serious question?? Who would apprehend an unknown murderer and notify unknown kin? No one, I suppose. Is it better if the police don't instead of a mall owner?
The individual will be missed and asked for by the family, and, under the scenario you describe, they will apprehend and deal with the criminal.
At least that's how I would do it if not for the interference of the "goverment".