(Most recent update: 8:39 p.m. ET.)
As investigators learn more about the surviving suspect in the Boston Marathon bombings and what Dzhokhar Tsarnaev and his older brother, Tamerlan, allegedly did, the initial theory is that "these two young men were working on their own," NPR's Dina Temple-Raston said Tuesday on Morning Edition.
Authorities continue to question 19-year-old Dzhokhar Tsarnaev, who remains hospitalized. He's being treated at a Boston hospital for a variety of injuries he sustained during gun battles with police on Friday. It's also possible he tried to kill himself before he was captured that evening in the Boston suburb of Watertown, Mass.
His 26-year-old brother died of injuries early Friday.
Investigators say they are hearing from Tsarnaev through notes he's writing in response to questions. Other than one comment from the magistrate who presided at his hospital-bed arraignment Monday, there's been no indication the suspect is able to speak more than a word or two at a time. The magistrate reported that Tsarnaev said "no" when asked if he could afford a lawyer.
According to law enforcement sources Dina has spoken with, the information they've gotten from the 19-year-old leads them to suspect — so far — that Tamerlan Tsarnaev was the "driving force" behind the bombings at the marathon (which killed three people and wounded more than 200).
The information Dzhokhar Tsarnaev has been giving to investigators, Dina added, has them theorizing the attack was "in a sense a homegrown plot with a little bit of an international flavor." Tamerlan Tsarnaev, who reportedly had grown increasingly interested in an extremist form of Islam in recent years, traveled to Russia at least once. The family has Chechen roots.
CNN says investigators also believe the brothers were influenced by things they read on the Internet, and may have learned about bomb-making there, as well.
An important reminder: The investigation is still in its early stages. Authorities will uncover much more evidence. The picture of what led the brothers to allegedly plant bombs at the marathon and then, allegedly, kill an MIT police officer and engage in a harrowing gun battle with authorities, could change substantially.
We'll be following Tuesday's developments and will update as news comes in.
Update at 8:39 p.m. ET. An 'Incidental Hero':
The Watertown man who found Dzhokhar Tsarnaev hiding in his boat says he is an "incidental hero."
David Henneberry tells WCVB that contrary to what's been reported, he did not see blood outside his boat. There was "no indication of anything." Instead Henneberry was simply going outside to fix some foam rollers that had fallen off.
When he rolled up the boat cover, he saw blood on the floor of the boat, then he looked toward the front and saw more blood. When he looked toward the engine, he saw a body. He did not see a face.
"It's surreal," Henneberry said. "I wasn't out on the prowl. I was out to see my boat and I stumbled upon this."
We encourage you to head to WCVB's site to watch the entire interview.
Update at 8:29 p.m. ET. Bought Fireworks In N.H.:
The New York Times reports that the older Tsarnaev bought fireworks at a store in New Hampshire, about an hour north of Boston.
"He came in and he asked the question that 90 percent of males ask when they walk into a fireworks store: 'What's the most powerful thing you've got?'" William Weimer, vice president of Phantom Fireworks, told the Times.
The paper adds:
"Mr. Tsarnaev settled on a reloadable mortar kit called a Lock and Load, which comes with a launch tube and shells, Mr. Weimer said. But Mr. Weimer said that even if the brothers had harvested all the powder from the shells Mr. Tsarnaev bought that day, he does not believe it would have yielded enough explosives to make the two pressure cooker bombs that exploded on Boylston Street and the other devices that the suspects had with them when they were chased by the police early Friday morning. The sale was first reported by The Wall Street Journal."
Update at 8:21 p.m. ET. FBI Contacted U.S. Multiple Times:
Russia contacted the United States multiple times about Tamerlan Tsarnaev, according to a senator briefed on the issue.
"In a closed briefing on Tuesday, members of the Senate Intelligence Committee learned that Russia alerted the United States about Tsarnaev in "multiple contacts" — including 'at least once since October 2011,' said Richard Burr, a Republican of North Carolina, speaking with reporters afterward.
"Senators said the briefing also revealed failures among federal agencies to share vital information about Tsarnaev, indicating, they said, that the US government still has not established a strong system to 'connect the dots' about would-be terrorists residing in America more than a decade after 9/11."
Update at 8:09 p.m. ET. 'A New Beginning For The Both Of You':
We wanted to share a video that's been making the rounds today. Celeste and Sydney Corcoran, a mother and daughter who lost limbs during the marathon bombing, were visited by marines, who had also lost limbs.
It's an emotional video that shows how Celeste and Sydney are coming to terms with their new reality. What's more, watch until the end, and you'll hear a good joke:
Update at 3:47 p.m. ET. Youngest Victim Laid To Rest:
The AP reports that 8-year-old Martin Richard, the youngest victim of the bombing was laid to rest today.
The AP adds:
"A private funeral Mass was held in the morning for young Martin Richard, followed by his burial, a family statement said. Only immediate family members attended. A funeral was also held for Massachusetts Institute of Technology police Officer Sean Collier, fatally shot three days after the bombing.
"'The outpouring of love and support over the last week has been tremendous,' the Richards' statement said. 'This has been the most difficult week of our lives and we appreciate that our friends and family have given us space to grieve and heal.'"
Update at 3:44 p.m. ET. Copley Square Reopening:
Some business people and residents were allowed back into their establishments and homes at Copley Square today.
"The reopening of Boylston began at 10 Tuesday morning, as Boston officials escorted business owners and staff, and residents, beginning with those buildings the furthest from the blast sites, as they are least likely to have to contend with dangerous structural issues or other hazards. ...
"'I don't know what to feel right now. It's a tense time,' said Con Coen, a Globe Cafe manager.
"The city is using the Hynes Convention Center as a staging area for residents and businesses, and by noon Ballroom B was mobbed, with waves of people flooding in. City officials are struggling to keep the crowd organized and are asking for patience as they explain how the scene will reopen."
Update at 2:15 p.m. ET:
Update at 1:30 p.m. ET. Sources Tell Washington Post That Tsarnaev Has Admitted Involvement:
"The 19-year-old suspect in the Boston Marathon bombings has told interrogators that the American wars in Iraq and Afghanistan motivated him and his brother to carry out the attack," The Washington Post reports, citing "U.S. officials familiar with the interviews" as its sources.
NPR has not independently confirmed that information. (See this note about how we cover news such as this.)
Update at 12:40 p.m. ET. Tsarnaev's Condition Now "Fair."
This just in from the U.S. attorney's office in Massachusetts:
"According to Beth Israel Deaconess, at noon today, Dzhokhar Tsarvaev's condition is listed as 'fair.' Releasing info at request of BIDMC."
BIDMC is Beth Israel Deaconess Medical Center in Boston.
Previously, Tsarnaev had been in "serious" condition.
Update at 12:15 p.m. ET. Photos From The Scene Of Friday's Gun Battle:
Andrew Kitzenberg of Watertown, Mass., has posted a series of pictures he reports taking in the early hours of Friday, when the Tsarnaev brothers allegedly engaged in a gun battle with police (during which they also allegedly lobbed explosives at the officers). It was dark, so the images aren't crystal clear. But they do offer a unique perspective on what happened.
Update at noon ET. Martin Richard, 8-Year-Old Victim, Has Been Buried:
A private funeral and burial were held Tuesday morning for the youngest of the three people killed in the bombings, 8-year-old Martin Richard of Dorchester, Mass. His parents, Denise and Bill Richard, released this statement:
"The outpouring of love and support over the last week has been tremendous. This has been the most difficult week of our lives and we appreciate that our friends and family have given us space to grieve and heal.
"A private Funeral Mass was celebrated this morning with immediate family. We laid our son Martin to rest, and he is now at peace. We plan to have a public memorial service in the coming weeks to allow friends and loved ones from our community to join us for a celebration of Martin's life."
Denise Richard and Martin's sister were severely wounded in the blast.
Update at 11:55 a.m. ET. Homeland Security Knew Of Older Brother's 2012 Trip To Russia, Napolitano Says:
"Homeland Security Secretary Janet Napolitano said Tuesday that her agency knew of alleged Boston bomber Tamerlan Tsarnaev's trip to Russia last year even though his name was misspelled on a travel document," The Associated Press reports from Washington, where Napolitano made her comments during a hearing on Capitol Hill about immigration legislation.
The wire service adds that:
"Napolitano said that even though Tsarnaev's name was misspelled, redundancies in the system allowed his departure to be captured by U.S. authorities in January 2012. But she said that by the time he came back six months later, an FBI alert on him had expired and so his re-entry was not noted."
Tamerlan Tsarnaev had been on the FBI's radar after Russian authorities asked in 2011 that he be questioned about "his shift toward increasing Islamic extremism," as CNN writes. The bureau says it "did not find any terrorism activity, domestic or foreign" on his part.
Update at 10:45 a.m. ET. Friends Are Convinced That Triple Murder In 2011 Happened On Sept. 11:
We reported Monday that prosecutors in Middlesex County, Mass., plan to take another look at an unsolved triple murder from 2011 in which one of the victims was a friend of Tamerlan Tsarnaev. On Tuesday, the Boston Globe reported that even though the death certificates of the victims say they died on Sept. 12 that year, friends and relatives are convinced they were killed on Sept. 11 — the 10th anniversary of the worst terrorist attacks in the nation's history.
Earlier, these were some of the morning's related headlines:
-- If Convicted, Tsarnaev Could Face Death Penalty. (The Washington Post)
-- "Bedside Transcript Of Boston Bombing Suspect Hearing." (The Boston Globe)
-- "Officials Say They Had No Authority To Watch Older Suspect." (The New York Times, which limits the number of stories that can be read for free.)
Note: As happens when stories such as this are developing, there will likely be reports that turn out to be mistaken. 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.