Within a day of the Oklahoma City bombing, officials had named their suspect: Timothy McVeigh. Within two days of the 9/11 attacks, investigators had zeroed in on al Qaeda as the perpetrator.
But as loved ones mourn the deaths of three people
and dozens of others remain hospitalized from the dual bombings Monday
near the finish line of the Boston Marathon, two questions continue to
hound authorities: Who triggered the attack, and why?
On Wednesday morning, a
federal law enforcement source with firsthand knowledge of the
investigation told CNN that a lid to a pressure cooker thought to have
been used in the bombings had been found on a roof of a building near
the scene.
While such clues may move
the investigation forward, they did not reveal whether the attack was
an act of domestic or foreign terrorism.