Why It’s So Easy to Build a Bomb and Not Get Caught

New York authorities discovered a suspicious device in Manhattan a few hours after an explosion rocked the Chelsea neighborhood on Saturday, injuring 29 people.

The device, found around West 27th Street, appeared to be a pressure cooker attached to wiring and a cellphone, officials said. A bomb squad is currently investigating the device, NYPD Commissioner James O'Neill said during a news conference Sunday.