Investigators Focus on Video to ID Bombing Suspect

Police and federal investigators are working to identify an image of a suspect in the Boston Marathon bombing from photos and security video, according to media outlets.

However, no arrest had been made, three separate government and law enforcement sources told Reuters. Police said they may make an appeal to the public for more information.

A news conference scheduled for Wednesday afternoon was postponed when the Boston federal courthouse was evacuated for an hour after a security scare, a government official said.

A security officer walked out of the courthouse and waved a green flag, signaling that employees could return.

A court official who declined to be identified confirmed the courthouse was reopened, but only to employees.

Earlier, CNN and other outlets reported that a suspect was in custody, citing law enforcement sources. But then CNN cited three sources who said no one was under arrest after all.

If investigators have identified a possible suspect based on security video, it would mark the most significant publicly disclosed break since Monday’s blast at the marathon finish line killed three people and injured 176 others.

Investigators were also searching through thousands of pieces of evidence from cellphone pictures to shrapnel shards pulled from victims’ legs.

Based on shards of metal, fabric, wires and a battery recovered at the scene, the focus turned to whoever may have made bombs in pressure-cooker pots and taken them in heavy black nylon bags to the finish line of the world-famous race watched by crowds of spectators.

A stretch of Boston’s Boylston Street almost a mile long and blocks around it remained closed as investigators searched for clues in the worst attack on U.S. soil since the hijacked plane strikes of 9/11.

Cities across the United States were on edge after Monday’s blasts in Boston.

Adding to the nervousness Wednesday was the announcement that envelopes containing poisonous ricin were found addressed to several lawmakers and to President Barack Obama in Washington, D.C. Police swept through the capitol following reports of suspicious envelopes and causing a flurry of activity on Capitol Hill.

The FBI said, however, that agents had found no link to the attack in Boston.

The blasts at the finish line of Monday’s race injured 176 people and killed three: an 8-year-old boy, Martin Richard, of Dorchester; 29-year-old Krystle Campbell of Arlington; and a 23-year-old Chinese woman, Lu Lingzi, a graduate student at Boston University.

No one has claimed responsibility for the attack.

“Whether it’s homegrown or foreign, we just don’t know yet. And so I’m not going to contribute to any speculation on that,” said U.S. Secretary of State John Kerry, who until January was Massachusetts’ senior senator. “It’s just hard to believe that a Patriots’ Day holiday, which is normally such a time of festivities, turned into bloody mayhem.”