英语文摘:Authorities Deny Media Reports of Arrest in Boston Marathon Bombings

U.S. law enforcement agencies are denying media reports that a suspect has been arrested in Monday’s deadly bombings at the Boston Marathon.

The FBI, federal prosecutors and police in Boston Wednesday all denied broadcast and print reports that a suspect has been arrested in the case.

Investigators told news agencies that footage from a security camera showed a man carrying, and then perhaps dropping, a black bag near where one of the twin explosions killed three people and wounded 176 others at the finish line of the annual race.

cnn reported that a key video was recorded at a local department store, and that video from a Boston television station also proved crucial in tracing a suspect's movement.

Word of a possible suspect sent reporters and onlookers flocking to the federal courthouse in Boston Wednesday afternoon. Federal security officials later ordered the courthouse cleared and moved people away from the building. No explanation for their action was given.

The investigators have collected a variety of fragments they say were part of the bombs, including pieces of pressure cookers that contained the explosives.  The lid of one of the pressure cookers was found on the roof of a nearby building.

Investigators released photos of mangled pressure cooker pieces, a few inches of a charred wire attached to a small box, a battery attached to red and black wires, a small nail and the head of a blood-stained zipper.  Authorities also found a circuit board believed to be part of one of the bombs.

A doctor at Massachusetts General Hospital said Tuesday survivors listed as critical are improving. He called the wounded "amazing people" and said he was touched to hear victims who lost a leg say how glad they are just to be alive. Numerous other victims have been released from hospitals after getting treatment for their injuries.

Two blasts seconds apart near the finish line of the marathon killed an 8-year-old boy, a restaurant catering manager and a graduate student at Boston University.