• After law enforcement sources told CNN that an arrest was made in Boston Marathon bombings, two senior administration officials and another federal official told CNN contributor Fran Townsend that no arrest happened.
• The bombs, which exploded 12 seconds apart near Boston Marathon finish line Monday, killed three people and wounded 178.
• Full story here; also, see CNN affiliates WBZ; WCVB; WHDH

[Updated, 10:30 p.m. ET] Two men seen in images near the finish line of Monday's Boston Marathon - moments before two bombs there exploded - are of "high interest" and are considered "possible suspects," a law enforcement official said.

A circular sent out Wednesday by authorities indicated the attached photos, showing the two men, were being sent around "in an attempt to identify the individuals."The official said the men were of interest because of where they were at a particular time and what they were carrying. One of the men is seen carrying a black backpack.

The source said that authorities had not yet identified the two men by name and that the photographs were not being released to the public for fear of impeding the investigation.

Updated at 9:27 p.m. ET] As of Wednesday night, Boston-area hospitals had released 112 of the 178 treated for injuries sustained in the marathon attack. Thirteen patients are in critical condition, the same number as was reported earlier in the day.

[Updated at 7:32 p.m. ET] The FBI has cancelled its Wednesday news briefing, the Boston police announced. Minutes earlier, police had said the federal agency would make a "brief statement" on the marathon case.

[Updated at 6:09 p.m. ET] "Every hour we're closer" to finding  the person or people responsible for Monday's twin bomb blasts at the finish line of the Boston Marathon, Massachusetts Gov. Deval Patrick told CNN's Wolf Blitzer on Wednesday.

[Updated at 5:45 p.m. ET] As of late Wednesday afternoon, Boston-area hospitals had released at least 103 of the 178 people treated for injuries sustained in Monday's attack near the Boston Marathon's finish line, according to a CNN tally.

Thirteen of those still hospitalized remain in critical condition, hospital officials said.

[Updated at 4:40 p.m. ET] A news conference about the Boston Marathon bombings that had been scheduled to begin at 5 p.m. has been postponed.

[Updated at 4:08 p.m. ET] Authorities investigating this week's attack want to question a man who was seen, on video, wearing a white baseball cap as a possible suspect in the case, two official sources with knowledge of the investigation told CNN.

One of the sources said the man had the hat on backwards and was wearing a light-colored hooded sweatshirt and a black jacket. The second source said that investigators have not identified this person.

[Updated at 2:58 p.m. ET] The FBI said in a statement Wednesday that no arrest has been made, "contrary to widespread reporting," tied to Monday's Boston Marathon attack.

Before that, following statements from the Justice Department and the Boston police that no arrest has been made, CNN's John King said this:

A federal law enforcement source told him that there has been "significant progress but no arrest." A Boston law enforcement said "we got him," but didn't clarify whether that means authorities have identified a suspect or arrested one.

Some federal sources say that even to say the suspect has been identified goes too far, but several sources in Boston say they have a clear identification.

[Updated at 2:48 p.m. ET] There have been no arrests in the Boston Marathon bombing investigation, according to Boston police and the Justice Department.

[Updated at 2:33 p.m. ET] There is conflicting information as to whether someone has been arrested in connection with the Boston Marathon bombings.

A federal law enforcement source told CNN's Fran Townsend that someone was arrested. But two senior administration officials and another federal official then told Townsend that there had been a misunderstanding among officials and that no one has been arrested.

[Updated at 2:23 p.m. ET] As news of an arrest spreads, a crowd has been gathering outside a federal courthouse in Boston.

[Updated at 2:10 p.m. ET] The last we heard, a law enforcement news briefing in the bombings case was scheduled for 5 p.m. ET today. We'll see if that holds.

Earlier today, CNN's John King reported that authorities had identified a suspect based on an analysis of video from a Lord & Taylor department store near the site of the second blast, and that video from a Boston TV station also helped. King cited a source who was briefed on the investigation.

[Updated at 2 p.m. ET] The arrest is based on two videos showing images of the suspect, a federal law enforcement source told CNN contributor Fran Townsend.

[Updated at 1:46 p.m.] An arrest has been made in connection with Monday's Boston Marathon bombings, sources tell CNN's John King and CNN contributor Fran Townsend. King's source is with Boston law enforcement, he said; Townsend's source is with federal law enforcement.

[Updated at 1:44 p.m.] While we wait for more information about the possible suspect, some recent information to pass on about one of the three people who were killed in Monday's blasts: Boston University said Lingzi Lu, a graduate student in mathematics and statistics, was killed.

She and two friends were watching the race near the finish line when the blasts erupted, BU Today reported. The second student was in stable condition at Boston Medical Center; the third student was not hurt, it said.

The university said that it had the family's permission to identify Lingzi Lu.

[Posted at 1:40 p.m.] Authorities may have had a breakthrough in the investigation of Monday's Boston Marathon bombings. Investigators believe they have identified a suspect in the Boston Marathon bombings, a source who has been briefed on the investigation told CNN's John King exclusively.

The breakthrough came from analysis of video from a department store near the site of the second explosion. Video from a Boston television station also contributed to the progress, said the source, who declined to be more specific but called it a significant development.

Earlier, a federal law enforcement source with firsthand knowledge of the investigation told CNN that a lid to a pressure cooker thought to have been used in the bombings had been found on a roof of a building near the scene.