Few cluesTo view this video please enable JavaScript, and consider upgrading to a web browser that supports HTML5 videoLena Baudach04/17/2013April 17, 2013US President Barack Obama has called the Boston marathon bombing a terrorist attack. Three people were killed and more than 170 wounded when two bombs exploded near the finish line of the famous race.https://p.dw.com/p/18H2XAdvertisement