By Mark Hosenball
(Reuters) - Investigators are seeking to locate and talk to at least two men pictured in images taken before two bombs exploded near the finish line of the Boston Marathon, law enforcement and national security officials said on Thursday.
Authorities are examining thousands of pictures taken by surveillance cameras, the media and ordinary citizens around the time the bomb blasts went off and are likely to try to talk to additional people, the officials said.
At this point, none of the men authorities are seeking to speak to are regarded as suspects in the investigation, said the officials, who asked for anonymity when discussing the investigation into the bombings that killed 3 people and wounded 176.
Homeland Security Secretary Napolitano said that video from the scene of Monday's bombings near the marathon's crowded finishing line had caught the interest of investigators.
"We have been collecting video from a variety of sources," she told a hearing in Congress. "There is some video that has raised the question of those that the FBI would like to speak with. I wouldn't characterize them as suspects under the technical term, but we do need the public's help in locating these individuals."
Although at least one leaked set of pictures have already been published in the New York Post, officials said there was an intense debate inside the government as to whether such photographs should be officially released and the public should be asked for help identifying people in them.
For the moment, the government is holding back from formally releasing the photos, fearing a repeat of a fiasco which occurred when similar photos, released following a bombing at the Atlanta Olympics in 1996, led to the arrest of security guard Richard Jewell, who turned out to be innocent.
"Images of individuals related to this investigation have not been released by the FBI to the public," a law enforcement official said. "Any images not released via FBI official channels should not be considered credible."
Another official briefed on the investigation said the inquiry was "very fast-moving," but that investigators were not closing in yet on any principal suspect and that arrests were not expected immediately.
(Additional reporting by Deborah Charles; Editing by Alistair Bell and Lisa Von Ahn)