F.B.I. Releases Images of Two Suspects in Boston Attack

The F.B.I. today released still and video images of two suspects in the Boston Marathon bombings - including a man who was seen setting down a backpack at the site of the second blast - and appealed for the public’s help identifying the men.

One was seen placing a dark-colored backpack outside the Forum restaurant, the site of the second bombing, just minutes before the explosion, said Richard DesLauriers, the special agent in charge of the F.B.I.'s Boston field office.

“Today we are enlisting the public’s help to identify the two suspects,” Mr. DesLauriers said at a news conference on Thursday evening in Boston.

In the video, both men are carrying backpacks, and wearing baseball caps, one a dark cap and one a white cap turned backward. They are walking along Boylston Street.

The images were located as investigators spent hours since Monday afternoon’s attack poring over surveillance videos from stores near the scenes of the two deadly blasts, as well as footage take on smartphones and by television crews filming the Boston Marathon. “Within the last day or so, through that careful process, we initially developed a single person of interest,” Mr. DesLauriers said. “Not knowing if the individual was acting alone or in concert with others, we obviously worked with extreme purpose to make that determination.”

After a concerted effort, he said, investigators determined that a second suspect had been involved.

Both men appeared to be wearing dark-colored zippered-front jackets. The first, whom Mr. DesLauriers called Suspect 1, wore a dark-colored baseball cap with a white emblem on it and markings on the front, a white T-shirt and tan pants. Visible around the edges of his cap was short dark hair. The man he identified as Suspect 2 wore a white baseball cap backward, with dark-colored pants. He had slightly longer curly hair. The men appeared to be wearing hooded sweatshirts beneath the jackets.

Mr. DesLauriers did not characterize the appearance of the men or offer an opinion as to their possible ethnicity or national origin.

Mr. DesLauriers urged anyone who has seen the men, or who knows who they are, to call 1-800-CALL-FBI (1-800-225-5324).