Many surveillance cameras do capture sound. It's important in investigations to know what was said during an incident. There are technologies like ShotSpotter

Many surveillance cameras do capture sound. It's important in investigations to know what was said during an incident. There are technologies like ShotSpotter - http://www.shotspotter.com/ http://www.shotspotter.com/ - which according to the NYT has enough fidelity to pick up things like "doors slamming, birds chirping, cars on the highway, horns honking." as well as conversations: http://www.nytimes.com/2012/05/29/us/shots-heard-pinpointed-and-argued-over.html?pagewanted=all http://www.nytimes.com/2012/05/29/us/shots-heard-pinpointed-...