Read the following excerpt from a police incident report and answer the question.

"Upon arrival at the scene, officers observed a male subject matching the suspect's description fleeing on foot. The officers gave chase and ordered the subject to stop. The subject ignored the commands and continued running. During the pursuit, the subject discarded a small plastic bag containing a white powdery substance. The substance was later field-tested and confirmed to be cocaine. The subject was apprehended after a brief struggle. A subsequent search of the subject's person revealed a loaded firearm and a large sum of cash."

According to the text, what specific action did the subject take that directly led to the discovery of the illegal substance?