An FBI crime scene investigator places an evidence marker on Boylston Street just past Berkeley Street near the scene of the Boston Marathon bombing April 17, 2013 in Boston, Massachusetts. Investigators continue to work the scene of two bomb explosions at the finish line of the marathon that killed 3 people and injured more than one hundred others. (Getty Images)
4:45 p.m. An FBI briefing that had been scheduled for 5 p.m. ET has been postponed as a result of the courthouse situation; unclear when it will take place.
4:01 p.m. The courthouse was evacuated due to a bomb threat and is currently being swept, Boston's WCVB reported.
3:45 p.m. The Boston courthouse was evacuated among conflicting reports that a bombing suspect had been arrested and was due to appear in court.
3:20 p.m. Federal courthouse in downtown Boston evacuated.
3:19 p.m. Here's CNN's original reporting that an arrest had been made:
3:15 p.m. Boston.com, part of the Boston Globe, is sticking to the story that a suspect is in custody. The Boston Globe's main site has walked back more fully.
2:56 p.m. The FBI says "no arrest has been made," media should "exercise caution and attempt to verify information" before reporting:
Contrary to widespread reporting, no arrest has been made in connection with the Boston Marathon attack. Over the past day and a half, there have been a number of press reports based on information from unofficial sources that has been inaccurate. Since these stories often have unintended consequences, we ask the media, particularly at this early stage of the investigation, to exercise caution and attempt to verify information through appropriate official channels before reporting.
2:44 p.m. CNN's John King reports an "identification" has been made based on video footage, but there is no one in custody and no arrest has been made.
2:40 p.m. The Boston Police Department has tweeted that "despite reports to the contrary, there has not been an arrest in the Marathon attack."
2:34 p.m. CNN's Joe Johns says two Justice Department sources have confirmed for him no arrest has been made and no one is in custody.
2:30 p.m. CNN contributor and former FBI assistant director Tom Fuentes says on air that three sources tell him there has been no arrest, no suspect is in custody.
2:24 p.m. New England news station NECN also reports no arrest has been made.
2:21 p.m. NBC's Frank Thorpe reports that House Homeland Security Committee Chairman Michael McCaul told him he spoke to the FBI minutes ago and was told no arrest had been made.
2:11 p.m. CBS News and NBC News both reporting no arrest has been made; CNN, Fox News and the Associated Press reporting it has happened.
2:05 p.m. The Associated Press is reporting the suspect is expected in federal court.
1:48 p.m. CNN is reporting an arrest has been made in the Boston Marathon bombings case; the arrest was made based on two videos showing the suspect at the bombing site.
Original story below:
Authorities have an image of a suspect carrying, and possibly leaving, a black bag at the site of one of the bombings at the Boston Marathon on Monday, CNN and the Boston Globe reported Wednesday afternoon.
Sources told CNN that officials identified the suspect using footage from a Lord & Taylor department store and a television station.
CNN's John King reported authorities made a "clear identification" of the suspect and described it as a breakthrough in the investigation.
King reported the footage was analyzed to such a degree that it was possible to discern facial features. King said the individual was described as "dark-skinned" but did not provide additional details because he said it was a sensitive issue.
This is a breaking news story. Updates will be added.
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