According to an article published on The Miami Herald shortly after the film’s release, Martin Scorsese uses the letter X throughout the film to signal that a character is destined for death. The visual motif appears no less 15 times throughout the film, sometimes subtly blending in with the background, and sometimes highlighted as a major part of the frame.
The multitude of ways the X appears throughout the film is truly impressive – they appear in graffiti behind a character walking down a dark alley, in crossing the window of a convict building, and they even appear as walkways in airports. Every appearance feels natural and rarely forced. This motif of X is also an homage to another classic gangster movie, the original “Scarface” (1932), which uses the same visual cue to denote whenever a dying character.
Each time they appear in “The Departed”, an X is placed next to a character destined to meet a terrible collapse. The incredible attention to detail put into this little motif is another sign of how great of a director Scorsese really is. It’s worth a simple review to see if you can catch them all.
https://www.looper.com/751496/why-the-xs-in-the-departed-mean-more-than-you-think/ Why the Xs in the departure make more sense than you think