Boston.com posted some of the details of the blast today.
The article reports:
Investigators have also recovered components of the bombs, enabling them to determine what they consisted of two 6-liter pressure cookers packed with nails, ball bearings, and other metal. The makeshift bombs were placed in black duffel bags, the official said.
Putting nails, ball bearings, and metal objects in these pressure cookers assures that there will be serious injuries. This type of bomb has been used in Iran, Iraq, Nepal, Pakistan, India, and Afghanistan.
Bombs with this type of shrapnel have been used by Hezbollah against Israel for a number of years.
This was a horrendous event. I am sure that those responsible will be found and held accountable. Forensic science is very thorough–there will be sufficient evidence to find the people who did this. However, that really doesn’t make life any easier for the families that were impacted by this event. Please remember them in your prayers.