Outrage has intensified across the US as protests, sparked by a grand jury decision not to charge a white police officer for fatally shooting an unarmed black teenager, spread to 170 cities in 37 states. <br /><br />In Ferguson, Missouri, where 18-year-old Michael Brown was killed by Officer Darren Brown, 2,000 national guard troops were deployed to protect homes and businesses from rioting and looting. <br /><br />The suburb of St Louis has a predominately black population and a white-dominated police force.<br /><br />The grand jury’s decision has sparked racially charged protests.<br /><br />The outrage on the streets now is more intense than the unrest that erupted in the immediate aftermath of the shooting.<br /><br />Police made 44 arrests and say protesters fired guns and hurled bricks at at them. Several police cars were set alight.