Except if you're a cop (on or off duty), fed, or employee in your car on the parking lot...then you have the RIGHT to carry a handgun or weapon (respectively) on the property of someone who doesn't want you to.
Or put another way they don't have the "right" to do anything about it.
[/quote]If the LEO is not there on official business, do you not have the right to ask them to leave? If there on official business, then they are the authority for the moment. You can't fairly say 'I know a murder was committed on my property, but you have no right to be here, now go...'. But if they are not there on official business and wander onto your property and sit down on your deck to have lunch by your pool, you have a right to have them leave.