How was the ex-soldier who leaked military secrets to a foreign espionage agency finally captured?

The ex-soldier, who possessed exceptional counter-surveillance skills and maintained a secretive profile, proved extremely difficult to apprehend despite suspicions of espionage activities. Chinese national security officers ultimately captured him by intercepting critical communications from a foreign espionage agency that contained specific instructions directing him to steal secrets from a particular military base. This intercepted order provided the necessary intelligence to track the suspect and establish a surveillance trail, finally leading to his arrest after what appears to have been an extended investigation.