There is a big difference between a cop standing by while someone he or she believes has a lawful right to enter the premises does so, and the cop actually enabling them to make entry.
First off, what state is this in? Who was this person he supposedly let inside, how did he let the person inside, and why did the person leave something there? Is this a roommate or ex boyfriend/girlfriend that you got miffed at? Or is this a friend who came over last week and left something there?
You can always report the unlawful entry to the police and, perhaps, report the officer's facilitating said entry to his or her supervisors or to some other agency such as the local prosecutor's office (if what the officer did was knowingly unlawful).
Oh, and just HOW is this a civil rights or discrimination issue????