Detection of Gunfire - What Is It?

Law enforcement officers cannot tap into microphone feeds and listen to what is going on around them. If gunfire is detected, the system autonomously alerts end users. There are web based and app based interfaces, which law enforcement officers and dispatchers have access to. From my experiences, I've heard gunfire nearby for myself, then received the alert shortly after the expediency of the alert lends me to believe that it is not processed or verified by living, breathing persons.