You know when a detective in a movie or tv show is trying to solve a big case, and they have that board on the wall with suspects, locations, etc, sometimes tied together with lengths of string? That board has a name: link chart.
These charts actually were used, although they weren't terribly efficient. Most police precincts don't have unlimited space in which to work, they had several big cases ongoing at once, and often only one board on which to post pictures and clues. The board also had to often remain covered so that no one outside the case would see which leads were being worked, possibly tipping off a suspect.
These days, there are software solutions that solve most of those issues, and that is what Present Day detectives will employ.
But we still love the ambience and feel of the good ol' Back In The Day Link Chart.