An employee let the suspect inside the warehouse Thursday night. That's when police said the suspect pulled out a gun and ordered the employee to the ground.
The employee then ran upstairs and called police.
Thinking the employee left the building, the suspect gave chase and locked himself out.
The suspect is described as a Hispanic male, 5 foot 4 inches tall, about 23 to 27 years old, weighing between 160 and 170 pounds.
He was seen leaving in a gold-colored four-door sedan.
If you have any information regarding this incident, you're asked to call El Segundo police at (310) 524-2284.