Why would a random man take pics of a house.. weird!?

could be some kind of criminal investigation, like private investigators trying to get answers about these people. or maybe they are traveling murderers, they go on vacations and hook up with people promising money or ual acts, then they get them alone in their hotel room and preform strange ual torture on them until they die from it and then they just go back home and live normal lives, or what the people around them think are normal lives.