NPR’s Tom Gjelten reported the big news: A senior law enforcement official told him that investigators have video of a man setting down a bag and leaving the scene. Despite conflicting reports, it turned out that the FBI had not made an arrest.

There was also good news: The New York Times reported that hospital officials said the 49 victims still at Boston-area hospitals would likely survive their injuries.

We’ll update this post as news happens. See this note about how we cover events such as this.

9:19 p.m. ET. Where Things Stand.

INVESTIGATION: There were conflicting reports in the early afternoon about whether a suspect was or was not in custody. As of 2:15 p.m. ET, sources with knowledge of the investigation were telling NPR’s Tom Gjelten that an arrest had not yet been made.

Law enforcement is expected to brief reporters later tonight.

Tom reports that a senior law enforcement official told him that authorities have reviewed video of a man setting down a bag and leaving the scene, but that does not necessarily make him a suspect. “We need more than that,” the official said.

CNN’s Deb Feyerick said what they know is the FBI has a picture of a suspect. What’s unknown is whether they’ve even identified the suspect.

NPR’s Dina Temple-Raston reports that an official familiar with the investigation told her the bomb was “a pressure cooker design with nails and ball bearings inside.” And Dina said on Morning Edition Wednesday that FBI investigators thought the key clue to finding who’s responsible would come from a photo or video taken by a spectator — evidence that “people don’t know is important, but the FBI looks at and sees some clue.” At the website of the FBI’s Boston Division, officials posted this appeal for help: “If you have any information that could be of assistance, please call 1-800-CALL-FBI (prompt #3). No detail is too small.”

DEATHS, INJURIES: The three people who were killed have been identified: Martin Richard was 8 years old and from suburban Dorchester. Krystle Campbell was 29 and lived in Medford, Mass. Lingzi Lu of China was a graduate student at Boston University.

About 180 people were injured. The New York Times reports that 49 victims remain in area hospitals. Officials told the paper all of them are expected to survive their injuries.

Update at 7:17 p.m. ET. Briefing Cancelled:

The scheduled 8 p.m. ET. briefing has been cancelled, the Boston Police Department just tweeted.

Update at 7:17 p.m. ET. New Briefing Time:

The Boston Police Department just tweeted that the FBI will “make a brief statement” at 8 p.m. We’ll bring you whatever news comes of that, as it happens.

Update at 7:12 p.m. ET. Likely All Victims At Hospital Will Survive:

The New York Times reports that hospital officials say the 49 victims still at Boston-area hospitals would likely survive their injuries.

At one point, more than 100 people were at area hospitals, so this is good news. The Times reports that 12 victims remain in critical condition.

Update at 4:31 p.m. ET. Press Briefing Postponed:

A briefing scheduled for 5 p.m. ET. has been postponed, the Boston Globe reports.

Update at 4:15 p.m. ET. Courthouse Evacuated, All Clear Given:

The John Joseph Moakley Federal courthouse in Boston was evacuated about an hour ago.

WBUR reports that the evacuation occured “because of a received bomb threat.”

At about 4:15, a man waving a green flag gave the all-clear. Adam Gabbatt, of The Guardian, tweeted that a court house official said: “We had a bomb threat; the building was clear; it’s being reopened for staff only.”

One other thing to keep in mind, authorities are scheduled to brief reporters at 5 p.m. ET. We will live blog that press conference.

Update at 2:48 p.m. ET. Justice Says No Arrest:

The Boston Globe, which earlier reported an arrest had been made, is now walking back its report, saying the U.S. Attorney’s office says no suspect has been arrested.

The AP, which also reported the arrest, has also walked back the report, saying “federal officials deny that Boston Marathon bombing suspect is in custody.”

As we told you earlier:

“CNN and the AP had been reporting that there a suspect in custody — or soon would be. CNN later reversed course, however, saying that additional sources were saying no one had been taken into custody. Meanwhile, The Boston Globe was saying “an arrest is imminent.” CNN later backtracked, though. And at 2:34 p.m. ET the Boston Police set the record straight, tweeting that ‘Despite reports to the contrary there has not been an arrest in the Marathon attack.’”

Update at 2:40 p.m. ET. Boston Police Say There’s Been No Arrest.

“Despite reports to the contrary there has not been an arrest in the Marathon attack,” according to a statement just posted on the Boston Police Department’s official Twitter page.

Update at 2:32 p.m. ET. CNN Backtracks; Says No Arrest Yet:

Three senior federal officials have now told her that there has not yet been an arrest, CNN contributor and former Bush administration national security adviser Fran Townsend just said on the air. Earlier, she was reporting her sources were telling her than an arrest had been made.

Update at 2:15 p.m. ET. No Arrests Yet, NPR Is Told:

NPR’s Tom Gjelten reports that his sources say there have not yet been any arrests made. As we’ve noted, though, both AP and CNN are saying that their sources tell them an arrest has been made.

Sources also tell NPR that there is video evidence showing a person who appears to have placed a bag at the scene that may have contained one of the bombs.

Update at 2:05 p.m. ET. Suspect In Custody, AP Reports:

The wire service just moved this “alert”:

“Law enforcement official: Boston Marathon bomb suspect in custody, expected in federal court.”

Update at 1:50 p.m. ET. Arrest Made Or About To Be?

“A law enforcement official briefed on the investigation says a suspect in the Boston Marathon bombings is about to be arrested,” The Associated Press reports.

CNN says an arrest has already been made. It’s getting that information from Fran Townsend, CNN contributor and former National Security adviser to President George W. Bush, who says that’s what she has been told by a federal law enforcement source in a position to know. It’s also getting word of an arrest from one of correspondent John King’s “Boston law enforcement sources.” NPR is working to get independent confirmation.

Update at 1:20 p.m. Suspect Seen On Video?

CNN is reporting that “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.” They told CNN that videos taken at the scene helped them zero in on the individual. The Boston Globe says it has been told by a source that “authorities have an image of a suspect carrying, and perhaps dropping, a black bag at the second bombing scene.” Authorities are set to brief reporters at 5 p.m. ET.

Update at 1:10 p.m. ET. Third Person Identified:

Boston University now writes that the third person killed was “Lingzi Lu … a graduate student in mathematics and statistics.” The New Yorker reports that she “was a native of Shenyang, a city in northeastern China about a hundred miles from the North Korean border. She attended Shengyang Northeastern High School, from which she graduated in 2008. She did well enough there to land a spot at the Beijing Institute of Technology, where she pursued a bachelor’s degree in international economics. In Boston, she had hoped to obtain her master’s. On Monday afternoon, Lu joined the marathon-watchers with two other overseas Chinese friends, partaking in one of their first and more cacophonous of American traditions.”

Update at 12:35 p.m. ET. “Significant” Progress?

CNN is reporting it has been told by authorities that “significant” progress has been made today on the investigation.

Update at 10:20 a.m. ET. Comparison To Vancouver Riot Investigation:

Following the riot in Vancouver, Canada, two years ago when the NHL’s Canucks lost the Stanley Cup championship, authorities requested photos and videos taken by the public to help find those who had set fires and thrown gasoline bombs. On WBUR this morning, correspondent David Boeri said more than 1 million photos were submitted and “1,200 to 1,600 hours of video.” In large part because of that evidence, police “were able to determine who had thrown bombs” and were responsible for other misdeeds.

Boeri said authorities in Boston are hoping the huge amount of evidence that’s likely in photos and videos taken by spectators and the media will help solve the marathon bombings.

Reminder: At the website of the FBI’s Boston Division, officials have posted this appeal for help: “If you have any information that could be of assistance, please call 1-800-CALL-FBI (prompt #3). No detail is too small.”

Update at 8:45 a.m. ET. Patients Improving, Doctor Says:

Most of the 10 or 11 victims being treated at Boston Medical Center who were initially in critical condition have made good progress, chief trauma surgeon Dr. Peter Burke just told reporters. He said only two patients remain in critical condition, and he expects them to survive their injuries. Burke added that 10 patients at the hospital are now considered to be in “serious” condition. An additional seven are said to be in “fair” condition.

Update at 8:15 a.m. ET. Mass. Governor Expects “Long, Painstaking Investigation”:

No “specific suspect or targets” have yet been identified, Massachusetts Gov. Deval Patrick (D) said on Boston’s WBUR this morning. And while “every hour, every day” brings investigators “a little closer” to finding out who was responsible, Patrick said everyone needs to “settle down and settle in for a long, painstaking investigation.”

“This is the kind of investigation that requires picking up tiny pieces [of evidence] and scouring blocks … a square inch at a time,” the governor added.

Update at 8:05 a.m. ET. Pressure Cooker Lid Found?

CNN is reporting that the lid of a pressure cooker has been found on the roof of a building near the site of Monday’s explosions.

Update at 8 a.m. ET: 100 Of The Injured Released, CNN Reports:

The latest estimate on how many people were injured, CNN says, is 183. And of those, about 100 are out of the hospital, the news network adds.

For More:

– Tuesday’s Developments.

– NPR’s Coverage.

– WBUR’s coverage.

Note: As happens when stories such as this are developing, there will likely be reports that turn out to be mistaken. Monday, for example, authorities at one point said they thought there also had been an explosion at the JFK Library in Boston. But it turned out there had been a fire, not an explosion, and there’s no known link at this time to the marathon attacks.

We will focus on news being reported by NPR, other news outlets with expertise, and statements from authorities who are in a position to know what’s going on. And if some of that information turns out to be wrong, we’ll update.

Take me back to the top of this post.

Copyright 2013 NPR. To see more, visit http://www.npr.org/.

A federal magistrate judge in Cleveland scheduled a preliminary hearing Monday for the five, who are described by the government as self-proclaimed anarchists. They were indicted on three counts each.

The court also must take up the question of setting bond for the suspects. The government wants them locked up pending trial.

The FBI says the five were arrested last week after setting the codes for what they thought would be an explosion to destroy a bridge south of Cleveland. But the bomb was a fake arranged by an FBI informant.

One defense attorney calls it a case of entrapment, with the informant guiding the way.

The remains of Captain Nicholas Rozanski of Dublin and Sergeant 1st Class Jeffrey Rieck of Columbus arrived Saturday at Delaware’s Dover Air Force Base. The attack also killed Sergeant 1st Class Shawn Hannon of Grove City.

Ohio State University’s Earle Holland grew up in Birmingham in the turbulent 1960s where he had a unique view of the civil rights struggle. His father was the editorial page editor of the influential and some would say liberal newspaper The Birmingham News.

“In the South you had the Ku Klux Klan of course. This was the time when George Wallace was the governor of the state of Alabama and he had ridden to his success on the claim of segregation now, segregation forever. It was a very volatile time not only for the races in general but also for anyone who would take a stance which was against the norm,” Holland says.

Which is exactly what Holland’s father did.

“His job was to provide the editorial stance in the newspaper which at the time was to try to recognize the fact that the South was changing and the traditional attitudes segregationist attitudes, unequal attitudes among the races were on the way out and it was time to embrace a new way of thinking. That clearly was not an attitude that much of the population in the region agreed with.

Bombings at the homes of local civil rights leaders became so common that Birmingham became known as “Bombingham.” Holland says that death threats became a way of life.

“As the paper and his editorials took a tougher and tougher stance, the newspaper learned that the Klan had issued death threats against the senior leadership of the newspaper and at that point in time we ended up having three armed guards on the house,” Holland says. “It was a situation that most people were not experiencing at that time.”

It took the tragedy of the 16th Street Baptist Church bombing to shake Birmingham to its core. Four girls – Addie Mae Collins, Carole Robertson, Cynthia Wesley and Denise McNair – were killed. They had just finished Sunday school.

“It was a Sunday morning and suddenly dad got a phone call and I remember him grabbing his coat and rushing out the back door and saying to my mom very briefly, ‘They’ve bombed a church they’ve killed four kids.’ That was perhaps the most critical event in the racial strife in Birmingham. It galvanized the opposition against that kind of violence regardless of race.

Birmingham was forced to confront itself. And its people changed.

“I think the general consensus among Southerners is the problem was not so much about race but about change. That people were more fearful of change more than they were of actual mixing of the races, That may be fantasy on my part but based on my experiences, I think that’s what it was, that Southerners as a class, tend to be very comfortable in the way things are and do not to respond to change as an opportunity in the way we all hope we do.”

Earle Holland is Assistant Vice President for Research Communications at Ohio State University.