First report - 1:42 p.m.: AP breaks the story that an arrest is imminent.
Update - 1:43 p.m.: Reuters reports that investigators do not have the name of a suspect, makes no mention of a suspect in custody.
Update - 1:46 p.m.: Citing the AP report and an independent source, CNN tells viewers that an arrest has been made.
CNN reports that video from a nearby Lord & Taylor department store was helpful in identifying a “dark skinned male” as a possible suspect.
Update - 1:51 p.m.: Reuters reports CNN's story that a suspect is in custody.
Update - 1:51 p.m.: In a live special report, ABC News reports that an arrest "may be imminent."
Update - 1:55 p.m.: In a live special report, NBC's Pete Williams says that no arrest has been made but individuals have been identified as persons of "great interest."
Update - 1:59 p.m.: CBS News reports that law enforcement sources are "very encouraged" by latest developments.
Update - 2:00 p.m.: FOX News reports that an arrest has been made.
Update - 2:02 p.m.: AP updates its story and reports that a suspect is in police custody.
Update - 2:03 p.m.: CBS reports that no arrest has been made.
Update - 2:05 p.m.: FOX News confirms that an arrest has been made.
Update - 2:06 p.m.: Boston Police scanner says that the suspect is en route to the Federal Courthouse.
Update - 2:08 p.m.: ABC reports that authorities are "close to identifying a suspect."
Update - 2:09 p.m.: NBC News doubles down, says no arrest has been made.
Update - 2:13 p.m.: CNN tweets that a suspect has been arrested.
Update - 2:18 p.m.: CBS reports that no arrest has been made, but a suspect was identified through cell phone tower logs.
Update - 2:24 p.m.: Reuters stands by its earlier statement that no arrests have been made.
Update - 2:25 p.m.: Boston Globe reports that the suspect is being taken to the US District Court in South Boston.
Update - 2:26 p.m.: Media descends on the Federal Courthouse in Boston.
Update - 2:32 p.m.: Citing multiple sources, NBC reports that no arrest has been made.
Update - 2:33 p.m.: Boston Police Department says there has not been an arrest.
Update - 2:36 p.m.: Boston Globe reports that there is NO suspect in custody and NO ONE is under arrest.
Boston Globe reports that this is a "dramatic change in status" of the investigation.
Update - 2:38 p.m.: CNN backtracks, says that no arrest has been made.
Update - 2:37 p.m.: BuzzFeed's Jessica Testa reports that Homeland Security officers are outside the federal courthouse.
Update - 2:42 p.m.: CBS reports that the suspect is a white male, describes clothing.
Update - 2:43 p.m.: FBI spokesperson tells Bloomberg News that no arrest has been made.
Update - 2:47 p.m.: AP walks it back, reports that there's no suspect in custody.
Update - 2:49 p.m.: FOX News backpedals, cites "conflicting reports."
Update - 2:52.: BuzzFeed's Jessica Testa reports on media chaos at the Boston federal courthouse.
Update - 2:53 p.m.: Conflicting reports appear on CNN's homepage.
Update - 2:58 p.m.: The FBI releases a statement confirming that no arrest has been made.
Update - 3:00 p.m.: CNN posts a correction on its Facebook page.
Update - 3:05 p.m.: AP says its law enforcement source stood by the information despite conflicting reports.
Update - 3:06 p.m.: Boston Globe says that the federal courthouse and a hospital where marathon victims have been treated are being evacuated.
Update - 3:07 p.m.: Reuters reports that the courthouse has been evacuated.
Update - 3:12 p.m.: Boston Globe confirms reports of the evacuation.
Update - 3:13 p.m.: Journalist posts panorama view of the media presence outside the federal courthouse.
Update - 3:17 p.m.: WCVB-TV Boston reports that the evacuation has been labeled a "Code Red."
Update - 3:18 p.m.: BuzzFeed's Jessica Testa reports that a K-9 unit has entered the courthouse.
Update - 3:28 p.m.: ABC News says courthouse was evacuated due to a bomb threat. No device was found.
Update - 3:29 p.m.: BuzzFeed's Jessica Testa reports that reporters outside the Boston federal courthouse have been forced to move across the street.
Update - 3:36 p.m.: BuzzFeed's Ryan Broderick reports that 4chan is claiming to have called in the courthouse bomb threat.
Update - 3:38 p.m.: Boston Globe reporter says courthouse evacuation caused by media presence.
Update - 4:19 p.m.: Boston Federal Courthouse gives all clear signal.
Update - 4:24 p.m.: Boston Globe reports that 5 p.m. FBI briefing has been cancelled.
Update - 4:36 p.m.: Reuters reports that the FBI has postponed the 5 p.m. press briefing.