"The Criminal"

The Criminal (犯人 han'nin) in Detective Conan is a substitute image for the culprits presented in Detective Conan and is usually depicted as a black or dark humanoid figure. It is used whenever the reader or watcher is to be made aware of the culprit's actions while attempting to keep his or her identity secret for the time being.

First appearances
Gosho stated that the idea of drawing the silhouette of the culprit was directly ripped off Kindaichi Case Files. The first black figures were very shady and roughly drawn in, and had no real body formation. They usually didn't even have a clearly drawn in face (as was shown in Opening 3). Sometimes, the figures resembled enough of the actual criminal's body that it could give away the true identity of the culprit.

Later changes
As the series went even further, the figure received a more human-like appearance with the gradual addition of eyes, noses, mouths, and finally muscles. However, the culprit still maintains a dark hue, lacking distinct clothing, body hair (including beards) and other physical anomalies (like overweightness). The figure remains very generic, looking more like a man or a genderless person (an exception in A Small Client episode because an evidence confirms that the murderer is female and thus the criminal has feminine appearance), keeping the audience guessing about the true identity and physical characterstics of the culprit in question.

Trivia

 * Though usually depicted as a criminal, the silhouettes are sometimes protagonists, but their identity has to be kept a secret from both the viewers/readers and/or Conan.
 * In Japan, a hooded jacket is sold with the face of "The Criminal" on the hood. When this is pulled down over the wearer's face, it makes them look like it.