Pressure cookers employed as Boston bombs

Updated We are learning more about the Boston attack, and the devices used.

At least one bomb at the marathon was packed inside a metal pressure cooker, hidden in a black duffel bag. It was likely set off by a timer. A person connected to the investigation says the explosives were placed on the ground and contained shards of metal, nails and ball bearings. More than 180 people were hurt, and a doctor who treated many of them confirms that objects were pulled from patients.

We have extensive coverage:

Part 1: Developments in the investigation; plus a moment of silence at Queen’s Park: