The 34-year-old man was looking through the window and into the home of a pair in Blekinge, southern Sweden, when he chanced to see them in a most intimate act.
Apparently upset by what he happened to see, he contacted police immediately and reported the lovers for sexual harassment.
But local police were having none of it, and closed the case.
"Having sex in your own home is not a crime," officer Johan Berntsson told the Sydöstran newspaper.
It remains unknown why the man was looking through the couple's window.