Was the Conduct of the Oswald Lineups Proof of His Innocence ?by Gil Jesus ( 2009 ) WHAT IS A POLICE LINEUP ? A police lineup is a process by which a crime victim or witness's putative identification of a suspect is confirmed to a level that can count as evidence at trial. The suspect, along with several other individuals ( which I will be referring to as "fillers" ) of similar height, complexion and build stand both facing and in profile. This is sometimes done in a special room