NEW HAVEN, Conn. (WTNH) – New Haven police say the ShotSpotter gunfire detection system is doing it’s job. In fact, the system alerted police to gunfire before any 911 calls were received. Four shots were detected on Second Street earl Wednesday morning. A woman visiting from Boston had witnessed the gunman firing the shots. She was noticeably shaken but provided the cops with her eyewitness account. She said she was parked near Greenwich Avenue. She spotted a “banged up” blue van driving back and forth for several minutes. She said the driver was a heavy-set black guy wearing a red sweatshirt. Eventually the van headed south on Greenwich Avenue. The woman heard the shots and ducked down in her car. The gunfire was reported to the officers on scene by at least one other person. During their search, the officers found bullet casings in the road. They were collected and will be subjected to forensic testing. The officers didn’t find the van or its driver. No one was hurt, nor was any damage to property reported.