The two brothers suspected of bombing the Boston Marathon appear to have been motivated by their religious faith but do not seem connected to any Muslim terrorist groups, U.S. officials said Monday after interrogating the severely wounded younger man. He was charged with federal crimes that could bring the death penalty.
Dzhokhar Tsarnaev, 19, was charged in his hospital room with using a weapon of mass destruction to kill, according to the criminal complaint.
The brothers, ethnic Chechens from Russia who had been living in the U.S. for about a decade, practiced Islam.
Dzhokhar Tsarnaev communicated with his interrogators in writing, a less-than-ideal format that precluded the type of detailed back-and-forth crucial to establishing the facts, one of two officials who recounted the questioning told the Associated Press. They spoke on condition of anonymity because they were not authorized to publicly discuss the investigation.
The two officials said the preliminary evidence from an interrogation suggests the Tsarnaev brothers were driven by religion but had no ties to Islamic terrorist organizations.
At the same time, they cautioned that they were still trying to verify what they were told by Dzhokhar Tsarnaev and were looking at such things as his telephone and online communications and his associations with others.
Link to '11 triple murder outside Boston?
Also Monday, the prosecutor's office in Middlesex County, Mass., outside of Boston, said it's become apparent that Tamerlan Tsarnaev, Dzhokhar's older brother who died last week during a gun battle with police, had very close links to a still-unsolved 2011 triple murder.
Tamerlan Tsarnaev was close friends with at least one of the three young men stabbed to death in an apartment in Waltham, Mass., in Sept. 2011. A spokeswoman for the county prosecutor's office told Reuters Monday afternoon that 'we are definitely going to pursue any new leads," adding that it was fair to say that investigators will check to see if Tsarnaev had anything to do with the crime.
Tsarnaev's close friendship with one of the victims, Brendan Moss, was also reported on the website Buzzfeed, which found friends who now wonder why Tsarnaev didn't attend any memorial services for Moss at the time.
The Boston Globe first reported that Tsarnaev told the owner of a gym the suspect used that Moss was his "best friend."
Cell phone use prior to bombing
In another development, the FBI says in an affidavit that Dzhokhar Tsarnaev was seen using a cellphone after placing a knapsack on the ground at an explosion site.
The document does not say whether suspect Dzhokhar Tsarnaev (joh-KHAR' tsahr-NEYE'-ehv) is thought to have used the cellphone as a detonator.
The affidavit also says one of the bombers told a carjacking victim, "Did you hear about the Boston explosion? I did that."
"He will not be treated as an enemy combatant," White House spokesman Jay Carney said of Tsarnaev. "We have used the federal court system to convict and incarcerate hundreds of terrorists."
Some Republican lawmakers had called for the 19-year-old Tsarnaev to be tried before a military commission as enemy combatant, without some of the rights defendants in civilian courts receive.
Carney, citing cases like the attempted bombing of Times Square and the so-called "underwear" bomber, said the civilian justice system has "repeatedly proven" it can handle terror cases.
Tsarnaev could face the death penalty if he is convicted in the bombings, which killed three people and wounded more than 200.
"Today's charges are the culmination of extraordinary law enforcement coordination and the tireless efforts of so many, including ordinary citizens who became heroes as they responded to the call for help in the hours and days following the Marathon tragedy," U.S. Attorney for Massachusetts Carmen Ortiz said in a statement.
The complaint gives the following account of the explosions at the marathon finish line:
Surveillance video shows two young men carrying large knapsacks turning onto Boylston Street from Gloucester Street at about 2:38 p.m. The two walk through the area, and at 2:45 p.m., Tsarnaev is seen "slipping his knapsack onto the ground" in front of the Forum Restaurant.
Tsarnaev remains in front of the restaurant, occasionally looking at and using his phone; about 30 seconds before the first blast he holds the phone to his ear. Tsarnaev finishes his call and the crowd around him is seen reacting to the explosion.
Tsarnaev, "virtually alone among the individuals in front of the restaurant, appears calm," the complaint says. He walks away, leaving his knapsack.
Ten seconds later, the second blast occurs.
"I can discern nothing in that location in the period before the explosion that might have caused that explosion, other than Bomber Two's knapsack," FBI Special Agent Daniel Genck writes in the complaint.
Tamerlan Tsarnaev's outbursts inside mosque
When preachers told congregants at a mosque in November that it was appropriate for Muslims to celebrate U.S. holidays such as the Fourth of July and Thanksgiving, a man who would later be a suspect in last week's the Boston Marathon bombing stood up to argue, the mosque said.
The Islamic Society of Boston Cultural Center on Monday told about that outburst by Tamerlan Tsarnaev and provided more details on a second one two months later that the group had previously described.
The group said in its statement that Tsarnaev, who was pronounced dead on Friday after a shootout with police, was not a member of its Cambridge mosque but sometimes attended Friday services and daily prayers over the last year or so. His younger brother, Dzhokhar, who was captured Friday and charged Monday with conspiracy to use a weapon of mass destruction, showed up sometimes for prayers, the group said.
Details to carjacking and shootout with cops
The complaint also gives details about the wild carjacking, shootout and manhunt that led to the death of his older brother, 26-year-old Tamerlan Tsarnaev, and ultimately Dzhokar's apprehension.
At around midnight on April 18, a man carjacked a vehicle in Cambridge by pointing a firearm at the victim and saying: "Did you hear about the Boston explosion?" and "I did that." They later picked up a second man; authorities say the carjackers were the Tsarnaev brothers.
Several "low-grade" explosive devices were found at the scene of the Tsarnaevs' shootout in Watertown, Mass. Those devices were made from pressure cookers that were the same brand as the bombs used at the marathon, among other similarities.
FBI agents also seized clothing from Dzhokar Tsarnaev's University of Massachusetts Dartmouth dorm room that was similar to the items worn by the Boston Marathon bomber.
When Dzhokar Tsarnaev was located in a bloodied boat, he had gunshot wounds to his head, neck, legs and hand.
Suspect remains hospitalized
Dzhokar Tsarnaev remains in serious condition at Beth Israel Deaconess Medical Center, according to federal prosecutors. He suffered a gunshot wound to the neck.
He was shot and wounded Friday while hiding in a boat parked behind a home in Watertown, Mass.
He is said to be communicating through writing, though the contents of the information has not been released, according to ABC News.
Was older brother radicalized?
Meanwhile, investigators are focusing on how Tamerlan Tsarnaev might have embraced a more strident form of Islam in the past few years. His parents told the Associated Press on Sunday that a trip last year to Dagestan and Chechnya last year was simply to visit relatives - and it was not to contact militants operating in that volatile part of Russia.
His father said Tamerlan Tsarnaev slept much of the time during his six month stay.
Indeed, there appears to be no direct evidence linking Tamerlan to militant groups, but there are hints nonetheless that some question his travels. The Chechen region has long been the center of an Islamic insurgency with the worst of the violence in Dagestan. At the time of Tamerlan’s stay, which began in January, 2012, militant attacks continued in the region.
The Caucasus Emirate, consider by many to be a terrorist organization, denied involvement in the Boston attack. "We are at war with Russia, which is not only responsible for the occupation of the Caucasus, but also for heinous crimes against Muslims," it said in a statement on the Kavkaz Center website.
But Tamerlan's mother said he was questioned upon arrival back in New York in July 2012. The FBI says its records show Russia had asked for information about Tamerlan in 2011, and the agency was informed he was a "follower of radical Islam" and preparing to travel to Russia to join unspecified underground groups.
The FBI, however, said it found no terrorism activity linked with Tamerlan.
Carney said the agency investigated the information "thoroughly," and did not find any terroristic activity, foreign or domestic, associated with the young man.
The Boston Globe reported that Tamerlan angrily disrupted a January talk at a Cambridge mosque when a speaker compared the Prophet Mohammed and the peace activist Martin Luther King Jr. It was the second time in recent months his faith collided with more mainstream Muslim theology at a public talk, the newspaper said.
And a man who says he was abducted by the suspects during a carjacking told authorities they only let him go because he "wasn't American," NBC News reported.
Moment of silence
Boston Mayor Thomas Menino and Massachusetts Gov. Deval Patrick led a moment of silence at 2:50 p.m. today, the time the first bomb exploded.
Cause of death not declared
A medical examiner is still working to determine how Tamerlan Tsarnaev died. The Massachusetts Executive Office of Public Safety and Security told the Associated Press this morning that it still isn't known exactly what killed the 26-year-old, who died during a getaway attempt.
Other developments over the weekend
-Thousands of participants in the London Marathon on Sunday paid tribute to those killed or injured in Boston.
-A wake for 29-year-old bombing victim Krystle Campbell was held Sunday at a funeral home in Medford, Mass. A private funeral is scheduled for today, followed by a memorial service in the evening for Lu Lingzi, 23, a graduate student from China also killed in the blast.
-Investigators believe the brothers were likely planning other attacks given that authorities found an arsenal of homemade explosives after a gun battle between police and the suspects.
-Patrick said surveillance video from the bombing shows Dzhokhar Tsarnaev dropping his backpack and calmly walking away from it before the bomb inside exploded. "It's pretty clear about his involvement and pretty chilling, frankly," Patrick said on NBC's "Meet the Press."
-The University of Massachusetts Dartmouth, which Dzhokhar Tsarnaev attended, reopened. The school had been closed Friday and Saturday due to the manhunt and subsequent investigation.