(CNN) — Investigators believe they have identified a suspect in the Boston Marathon bombings, a source who has been briefed on the investigation told CNN’s John King exclusively.
The breakthrough came from analysis of video from a department store near the site of the second explosion. Video from a Boston television station also contributed to the progress, said the source, who declined to be more specific but called it a significant development.
Earlier, 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.
A press Conference has been scheduled for 5pm EST.
CNN’s Fran Townsend, Matt Smith, Dave Alsup, Henry Hanks, Susan Candiotti, Rande Iaboni, Gloria Borger and John King contributed to this report.