If these devices came from designs from some website, whatever they were, they worked good enough and had to come from some experienced group with good designs. However, this also means whoever did it, was able to access some means for testing. In this day, having blasts going off on your property would attract some notice and be quite risky. Having access to a way for testing would be almost impossible. I just can’t imagine something working so well right out of the box, without being tested. In my opinion, making such successful devices is not simple. For that reason, it had to take someone with experience or someone who had access to some way of testing to prefect the performance of such a device. The latter makes it more unlikely. It is the person with experience that I say is the most likely and such came from a terrorist group that does such things frequently.
We are learning that the bomb was made out of a pressure cooker. There was talk that such a method was being used in Afghanistan. They say that the method of bomb construction tells much about the person making them. I hope they get all their pieces together and slam this guy (or guys).
You wrote on April 15th:
I think somebody accessed an Islamist web site and was able to get blueprints for an IED that used ball bearings as means to generate sharpnel. It sounds more like an bomber inspired by al-Qaeda, something terrorism experts are increasing fearing since the perp may not be able to be traced back to any al-Qaeda connections.
Here is the latest:
According to a report in the Mirror, an investigator said there is “no doubt the brothers were not acting alone. The devices used to detonate the two bombs were highly sophisticated and not the kind of thing people learn from Google. They were too advanced. Someone gave the brothers the skills and it is now our job to find out just who they were. Agents think the sleeper cell has up to a dozen members and has been waiting several years for their day to come.”