Detectives Follow Footprints

Ace Dick is a very good detective. How do we know this? He can follow the obvious trail of footprints directly to the culprit!

Much like Thief Bag is about an image summarizing a profession, someone following footprints (preferably with a magnifying glass) is a detective or investigative sort. A common gag in cartoons is for the character to pick up one of the footprints for a better look or to end up following their own footprints around.

This trope is pretty common in children's media.

Examples of Detectives Follow Footprints include:

Comic Books

Donald Duck comics also get a lot of playing with this trope. For instance, the comics have a whole subtrope for characters exploiting the trope, knowing they are being followed, manipulating the footprints to mislead the pursuers.

Literature

The Sherlock Holmes stories showcase Holmes' ability to ascertain several physical traits and describe the actions/mindset of the perpetrator of a crime by analyzing the footprints at a crime scene - in fact, Holmes claims to have published several papers on the subject.

Newspaper Comics

The Far Side has done this in at least 1 cartoon.

Video Games

A series of sidequests in Epic Mickey, given to you by the detective, involves you following footprints to the same guy every time, where you have to buy back stolen objects.
Happens in Chrono Trigger when your gate key is stolen by reptites. The section of the game is even called "Footsteps! Follow!".
The introduction scene of Agent Jayden in Heavy Rain sees him following a footprint trail (among other things).

Webcomics

Eight Bit Theater has a non-detective example, where Fighter shows off his tracking skills by describing the footprints he's following. They're his and Black Mage's own trail.

Western Animation

A constant trope in Scooby Doo.
Daffy Duck short The Great Piggy Bank Robbery. While Daffy (Duck Twacy) is inside a house, he follows foot prints (using a magnifying glass) up a wall, across the ceiling and down to a ~~mouse~~ rat hole.
The intro animation to Sylvester and Tweety Mysteries features this very prominently.
In one Winnie the Pooh story, Pooh is following a set of tracks on the snow, wondering who or what made them. Piglet joins him, and soon discover a second set of tracks. Then they keep going and find two more set of tracks. What they don't realize is that they've been walking in circles, following their own tracks.

Real Life

While footprints are rarely as obvious as portrayed in cartoons, they can be a powerful clue for forensic scientists. Shoe models are cataloged, so the police can check sales of that particular shoe, which can be tied to a suspect's credit card. The degree of indentation and spacing can determine height and weight, narrowing down the suspects. That being said, the duty of real life detectives in police departments is mainly to conduct big-picture investigative work such as conducting interviews and interrogations, searching records, and analyzing evidence for patterns, while the actual following of footprints is a much smaller part of the job, one usually given to forensic analysts (for examining physical evidence) or uniformed street officers (for hunting down suspects).