LIVE BLOG - Boston Marathon Bombing: FBI, Intelligence Community Begin Investigation Into Terror Attack's Planning, Possible Outside Help

All Times Are EDT:

Update Monday 8:45 a.m.: The father of the alleged Boston suspects said he plans to fly to the United States "to clear up many things," the Associated Press reported Monday.

Update Monday 6:10 a.m.: Evidence continued to amount early Monday of an increasingly radical turn by Tamerlan Tsarnaev, 26 and the older of the two brothers accused of the Boston bombing. Tamerlan angrily disrupted a speaker at a January talk at a Cambridge mosque, Boston.com reported.

Meanwhile, his brother, Dzhokhar, 19, captured alive Friday night, remains in serous condition and under heavy guard at Beth Israel Deaconess Medical Center. He has a gunshot wound to his throat.

Update Sunday 11:55 p.m.: One of the most bizarre things about the now-hospitalized Boston Marathon bombing suspect Dzhokhar Tsarnaev is the discovery of his Twitter account, which he frequently used, even after he and his brother allegedly set off a pair of bombs that killed three people and injured 180. One of the most unsettling images posted to the account was a black BMW bearing a license plate reading “Terrorista #1.”

Update Sunday 9:45 p.m.: Dzhokhar Tsarnaev, listed in serious condition at the Beth Israel Deaconess Medical Center in Boston, is conscious and replying to questions via the written word, USA Today quoted a law-enforcement official as saying.

Update Sunday 6:23 p.m.: The Boston Marathon bombing suspect seemed to be failing a number of his college courses before the April 15 terrorist attack that killed three people.

Update Sunday 5:12 p.m.: If the late Boston Marathon bombing suspect Tamerlan Tsarnaev carried out the April 15 terrorist attack with his now-hospitalized brother Dzhokhar Tsarnaev, then IBTimes may have collected a few answers to the many questions about the boxer without "a single American friend."

Update Sunday 4:15 p.m.: Boston Mayor Tom Menino and Massachusetts Gov. Deval Patrick have called for a moment of silence Monday to mark the one-week anniversary of the marathon bombings, WCVB reported. Authorities said the moment of silence will take place at 2:50 p.m., followed by the ringing of bells across the region. Menino and Patrick are calling upon all residents to join in honoring the victims of the attacks and their families and are encouraging the public to visit onefundboston.org to make a donation to help the victims.

Update Sunday 3:10 p.m.: Fifty-two victims of Monday's bombings remain hospitalized Sunday afternoon, with three in critical condition, NBC reported.

Update Sunday 2:17 p.m.: Dzhokhar Tsarnaev’s wounds indicate that he tried to kill himself before being taken alive, an unnamed law enforcement official told The New York Times Sunday. His gunshot wound to the neck “had the appearance of a close range, self-inflicted style,” a senior law enforcement official said. “He’s not in good shape.” The wound, and the fact that Tsarnaev is under sedation, have kept him from speaking. Forensic experts often can determine how far the weapon was from the body when it was fired based on the appearance of the wound.

Update Sunday 2 p.m.: A videotape shows Dzhokhar Tsarnaev placing a backpack at the Boston Marathon bombing scene, Massachusetts Gov. Deval Patrick said on NBC’s “Meet the Press” Sunday. “The videotape is not something I’ve seen,” Patrick said. “It’s been described to me in my briefings, but it does seem to be pretty clear that this suspect took the backpack off, put it down, did not react when the first explosion went off, and then moved away from the backpack in time for the second explosion. So pretty clear about his involvement and pretty chilling, frankly, as it was described to me.”

Update Sunday 1:50 p.m.: Family and friends of Krystle Campbell are gathering for a wake for the bombing victim Sunday, the Associated Press reports.

The wake is being held at a funeral home in her hometown of Medford, just north of Boston, where the 29-year-old restaurant manager was raised and graduated from high school in 2001. A private funeral is planned for Monday at St. Joseph Church.

Update Sunday noon: “We don't know if we'll ever be able to question the individual,” Boston Mayor Tom Menino said Sunday morning on ABC’s “This Week.”

“I hope that the U.S. attorney, Carmen Ortiz, takes him on the federal side and throws the book at him,” Menino added. “These two individuals held this whole city hostage for five days.”

Update Sunday 10:50 a.m.: The FBI's Boston office released the following statement on Sunday: "According to Beth Israel Deaconess Medical Center, Dzhokhar Tsarnaev remains in serious condition. The FBI is releasing this information at the request of the hospital."

Earlier, Boston Police Commissioner Ed Davis said on "Fox News Sunday" that Tsarnaev is in "no condition to speak," but is "progressing." He added that his assessment of the amount of explosives the two suspects possessed led him to surmise they were planning more attacks.

Update Sunday 9 a.m.: A North Caucasian rebel site denied Sunday any link to the Boston Marathon bombings that have been blamed on two Chechen immigrants.

"The command of the Vilayat Dagestan mujahedeen... declares that the Caucasus fighters are not waging any military activities against the United States of America," the Kavkacenter.com website said, according to Agence France-Presse. "We are only fighting Russia, which is not only responsible for the occupation of the Caucasus, but also for monstrous crimes against Muslims."

The FBI is investigating possible links between brothers Dzhokhar and Tamerlan Tsarnaev to the “Caucasus Emirate” movement led by Doku Umarov. Authorities are particularly interested in the Vilayat Dagestan offshoot of Umarov's group.

Update Saturday 11:58 p.m.: Politico has a well-rounded discussion of the legal issues currently surrounding Dzhokhar Tsarnaev because of his alleged role in the Boston Marathon bombings April 15: "Next For Boston Suspect: 5 Legal Questions." Check it out.

Update Saturday 10:16 p.m.: Dzhokhar Tsarnaev may have attempted to commit suicide before the Boston Marathon bombing suspect was captured Friday night, CBS News reported Saturday night. Noting Tsarnaev apparently has bullet wounds in his neck and leg, correspondent John Miller pointed out: "[Investigators are] saying that wound to the back of the neck is very possibly a suicide attempt. They say it appears from the wound that he might have stuck a gun in his mouth, and fired, and [the bullet] just went out the back of his neck without killing him."

Update Saturday 8:42 p.m.: Boston Marathon bombing suspect Dzhokhar Tsarnaev may or may not want to talk to authorities about his alleged crimes, but he might not able to do it. Literally. The currently hospitalized Tsarnaev has an injury to his throat that could make talking hard, a federal official with knowledge of his condition told CNN Saturday. The wound could delay answers to questions about the motive for the April 15 terrorist attack purportedly perpetrated by Tsarnaev and his late brother Tamerlan Tsarnaev.

Update Saturday 7:32 p.m.: To absolutely, positively nobody's surprise, the U.S. taxpayer will be footing the bill for the legal counsel to be given Dzhokhar Tsarnaev, the currently hospitalized Boston Marathon bombing suspect. Miriam Conrad, head of the Massachusetts Federal Public Defender office in Boston told Reuters via email that "we have been informed that we will be appointed after charges are filed." The office represents criminal suspects who cannot afford an attorney.

Update Saturday 6:17 p.m.: Check out a handful of photographs released by the Massachusetts State Police via Twitter Saturday that show how high-tech tools helped in the manhunt for Boston Marathon bombing suspect Dzhokhar Tsarnaev in Watertown Friday.

Update Saturday 3:55 p.m.: The search for Boston Marathon bombing suspect Dzhokhar Tsarnaev may be over, but posts on his VKontakte social-network page are continuing into the weekend: More than 8,000 bombing-related posts have been made on Tsarnaev's VKontakte page, USA Today reported. VKontakte, comparable with Facebook, is available in several languages, and it is especially popular among Russian-speaking users around the world, the newspaper said.

Update Saturday 2:40 p.m.: U.S. officials said a special interrogation team for so-called high-value suspects is preparing to question Boston Marathon bombing suspect Dzhokhar Tsarnaev without reading him his Miranda rights, as they would employ a rare public-safety exception, the Associated Press reported. Tsarnaev is currently hospitalized in serious condition under heavy guard, AP said. As a result, any interrogation may have to wait for a while.

Update Saturday 1:14 p.m.: While Boston Marathon bombing suspect Dzhokar Tsarnaev recovers in serious condition at Beth Israel Deaconess Medical Center in Boston on Saturday, authorities are focused on finding a motive for the heinous act allegedly carried out by him and his late brother Tamerlan Tsarnaev, as Reuters reported. Officials also want to know whether the suspects acted alone or in concert with others.

Update Saturday 11:56 a.m.: Thousands of images from the era's indespensible mobile device -- smartphones, combined with superfast FBI/law-enforcement software that can scan images/video very quickly -- produced suspect location leads far quicker than even a decade ago. Furthermore, a "drone robot" enabled law-enforcement personnel to probe a dangerous location, in this case, a boat one suspect was hiding in, with less risk to life.

Update Saturday 11:40 a.m.: In addition to the extensive "flood the zone" dragnet that tightened the transportation noose around the two alleged suspects, two other postmodern era inventions aided in the duo's capture - and undoubtedly are likely to increasingly aid law enforcement in the future: 1) the prevasiveness of cameras among the public and 2) the use of high-tech "drone robots" to observe dangerous locations.

The cameras, standard on almost all smartphones, rendered thousands of photos and videos that provided evidence for investigators. Further, when combined with very fast FBI image/video scan software not available commercially, the result was an ability to develop leads in the case and information on the suspects' possible location far quicker than law enforcement officials could achieve even a short decade ago.

Meanwhile, the "drone robot" simply enabled law enforcement officials to observe dangerous locations that otherwise would not be probed without a high risk to SWAT/police personnel.

Update Saturday 10:35 a.m.: A hospital spokesperson said alleged Boston bombing suspect Dzhokhar Tsarnaev, 19, captured by authorities Friday night, is still alive, but the FBI asked that the hospital give no updates on his condition, ABCNews reported. When Dzhokhar was apprehended in boat in the backyard of a Watertown, Mass. home, he was bleeding badly and was too weak to resist any police containment effort, official said.

The FBI, other law enforcement officials, and the U.S. intelligence community are hoping Dzhokhar survives, as information obtained from him may prove pivotal in determining the duo's motives for the attack, whether there are other "sleeper cells" - covert terrorists in the United States - and/or if they had help from known terrorist organizations/networks.

Update Saturday 8:55 a.m.: In the year before the attack, the two bombing suspects did not slip entirely below the U.S. intelligence community's radar. The FBI said in a statement it interviewed alleged marathon bomber Tamerlan Tsarnaev in early 2011, after receving a tip from a foreign government official that Tamerlan was "a follower of radical Islam" and was preparing to leave the United States to join an underground organization. The FBI interviewed Tamerlan and his family, and conducted other checks, but "did not find any terrorism activity" at that time.

Update Saturday 8:05 a.m.: FBI and state/local investigators have started their investigation into whether the two Chechen brothers suspected of undertaking the Boston Marathon bombings acted alone or had help.