Yea, kinda like, “a neighbor reported something illegal is going on in your home, can we come in and take a look around?”
or
” Sir, do you realize how fast you were going? Can I take a look in your vehicle?”
or
how bout running late for your flight, “ excuse me sir, spread your legs, we need to pat your boy’z down, then walk through the naked scanner for us please!”
or
“What are you doing on this road this time of night? Where are you going, where are your papers? Going to pat you down for your and our safety...against the car!”
The rights of a man fighting a charge of homicide to a fair trial and facing the possibility of years in prison trump the (obviously very low) expectation of privacy of a FaceBook user - and especially of a dead FaceBook user.
In none of your examples was there any urgent motivation on the part of the law enforcement officials approaching the need of the Defendant in the case at hand.
Regards,