Tedec has discovered, as expected, that most of the terrorist bombs are made according to the plans found in "How to be a Terrorist" manuals captured from al Qaeda members (and found in abundance in Afghan al Qaeda training camps). These manuals were compiled from material originally developed in the Soviet Union and provided to terrorist organizations the Soviets secretly supported until the Soviet Union collapsed in 1991.
U.S. troops in Iraq do some unusual things, but sometimes do them so often that the media doesn't even notice. One military drill is the CSI (Crime Scene Investigation) the troops, along with some civilians, do after every attack on coalition troops. The army, if asked, says they want to find out exactly what happened so they can adjust their tactics to make it harder for the enemy to hit them in the future. But you can take this sort of CSI a lot farther, and in 2003 the U.S. government sent up Tedac (Terrorist Explosive Device Analytical Center). This organization was secret until recent testimony in Congress revealed it's existence. Tedec draws its staff from the FBI, Defense intelligence Agency, CIA, the National Security Agency, the Bureau of Alcohol, Tobacco and Firearms and other intelligence agencies not named. What Tedec tries to do is identify types of bombs, and how many different bomb makers are out there. Making bombs for terrorist attacks is a tricky business, and there are several known accidents where bomb makers committed errors and blew themselves up. There have undoubtedly been other such accidents that remain secret. Israeli intelligence has long known that only a handful of "engineers" have been making the bombs used for terrorist attacks against Israeli civilians. So the Israelis made a major effort to identify the "engineers", and kill or capture them. Once a lot of the engineers were out of the way, there were fewer bombing attempts, and more explosions in Palestinian areas, when less skilled "engineers" screwed up while building bombs.
But Tedec was looking for sufficient evidence to identify individual bomb makers. Even when working from the same plans, each "engineer" will leave behind tell tale signs identifying him. Tedec is also able, at times, to recover fingerprints and DNA of the engineer. If you compile enough data like this, especially if you are using powerful computer database tools to store and massage the data, eventually you are going to obtain leads that will lead you to your engineers. Once you start taking the engineers out of the bomb making business, there are fewer bombs going off.