Boston Marathon bombing suspect Dzhokhar Tsarnaev is awake and responding sporadically in writing to questions, authorities said. Investigators are asking about other cell members and other unexploded bombs, law enforcement sources told ABC News. 
 
 Previously officials said Tsarnaev was in no condition to be interrogated. 
 
 Tsarnaev, 19, is being treated at Beth Israel Deaconess Medical Center in Boston, where he is listed in serious but stable condition, with wounds to the neck and throat area, according to sources. 
 
 The bombing killed three, including a young boy, and wounded about 170. An MIT officer was allegedly killed by Tsarnaev and his brother Tamerlan and a Boston transit cop was badly wounded in a subsequent shootout. 
 
 The FBI is still collecting evidence from the Monday's blast site, mainly from the sides of buildings and the bleachers. 
 
 Boston Police Commissioner Ed Davis in a news conference Sunday that the circuit board to at least one of the bombs had wires crudely soldered to it and is confident ATF agents will put that bomb back together piece by piece and tell us what it was made of. 
 
 Engineers are also checking the structural integrity of buildings near the scene before it fully reopens. Boston Police plan to start returning personal items to people who left behind their things on Monday. 
 
 Boston Mayor Thomas Menino said it is time for the city to move forward. 
 
 "I'm working hard over the last several days develop a plan to reopen Boylston Street now the most famous street in the world," Menino said at the Sunday news conference. 
 
 Possible Charges at State and Federal Levels 
 
 Tsarnaev could face charges at the state and federal levels, but Massachusetts has no death penalty. 
 
 Menino hopes federal authorities "throw the book at him," which would include the possibility of execution. 
 
 "I hope that the U.S. attorney takes him on the federal side and throws the book at him," Menino said on "This Week." "These two individuals held this city hostage for five whole days." 
 
 "They should not do that -- that's what these terrorist events want to do, hold the city hostage and stop the economy of the city." 
 
 RELATED: 'This Week' Transcript: Mayor Thomas Menino 
 
 Menino said he agreed with the decision to shut down the city Friday because of multiple events, including the discovery of a pipe bomb unrelated to the marathon attack. 
 
 "At that time we found a pipe bomb at another location in our city of Boston," he said. "Another individual was taken into custody." 
 
 Menino did not elaborate on the pipe bomb incident. 
 
 He said he believed the Tsarnaev brothers acted alone when they allegedly set off two bombs at the Boston Marathon finish line. 
 
 He also said he thought that Tamerlan Tsarnaev, 26, who died after a gun battle with police, "brainwashed or manipulated" his 19-year-old brother, who was taken into custody Friday. 
 
 It's unclear when Dzokhar Tsarnaev will be able to talk, but a special interrogation team is at the ready, sources said. 
 
 He apparently knows that his brother died after a Thursday night gun battle with police, sources say. 
 
 Authorities had launched Friday a manhunt for Tsarnaev, who managed to escape one block outside a police perimeter. Residents of greater Boston were told to stay in doors, as police hoped to find and apprehend Tsarnaev alive. 
 
 Authorities zeroed in on a boat in a Watertown, Mass., backyard after they received a tip from homeowner George Henneberry, who saw something was amiss. 
 
 PHOTOS: Boston Bombing Suspect Manhunt 
 
 An infrared camera with a bird's-eye view of the moments before Tsarnaev's capture gave authorities an idea of what to expect as they methodically closed in on the Boston Marathon bombings suspect. 
 
 Police believe Tsarnaev was initially wounded Thursday night in the gun battle that ended in his brother's death. Police said they found blood in a car he abandoned and blood at a house. 
 
 RELATED: Boston Bomb Suspect Captured Alive in Backyard Boat 
 
 The thermal-imaging camera showed Tsarnaev was able to move around inside the boat, as the FBI SWAT team brought in a robotic device to approach the boat and peel back a tarp, giving authorities a clear view of the suspect. 
 
 At least two flash grenades were thrown into the boat, designed to disorient Tsarnaev, who authorities feared might have been wearing a suicide vest. 
 
 They were then able to move in, rushing Tsarnaev to Beth Israel medical center for treatment, where he has remained under heavy guard. He was not wearing a vest. 
 
 It was unclear whether he was hit by a final exchange of gunfire Friday. 
 
 Tsarnaev is in the same hospital where his brother, Tamerlan, 26, was brought early Friday after a shootout with police. Tamerlan died of his wounds. 
 
 The Investigation 
 
 Investigators, who are expected to include the country's elite counterterrorism unit, are hoping that Tsarnaev survives because they are intent on determining what triggered his and his brother's alleged involvement in the attack and whether they had any help. 
 
 One focus of the probe so far is a six-month trip Tamerlan Tsarnaev took to the semi autonomous Russian province of Dagestan in 2012. Dagestan has become a hotbed of militant Islamic activity. 
 
 The FBI acknowledged it interviewed Tamerlan Tsarnaev at the request of Russian authorities, but after looking at his phone records, websites he visited and associates, the FBI found he had no ties to terror. 
 
 Zubeidat Tsarnaeva, the suspects' mother, said her sons couldn't be responsible for the Boston Marathon bombings because Tamerlan had been on the FBI's radar. 
 
 "My son would never do this. It is a set up," she said. "He was controlled by FBI like for five, three, five years. They knew what my son was doing." 
 
 RELATED: Bombing Suspects' Mom: 'My Family Is in the Dirt' 
 
 After Tamerlan Tsarnaev had been checked out, FBI officials said the monitoring had to stop by law because they found nothing incriminating. 
 
 "There are too many people in this country just like him that are touching extremist websites that are espousing things that aren't particularly kind to Americans. But that's not against the law here," ABC News consultant and former FBI special agent Brad Garrett said. 
 
 Boston Starts to Heal 
 
 After a week of tragedy, terror and living on edge, the greater Boston area is finally breathing a sigh of relief. 
 
 "We got our guy and very proud of it and we want Watertown to back to normal; we want Boston to go back to normal," Watertown Chief of Police Edward Deveau told ABC News. 
 
 On Sunday, Cardinal Sean O'Malley called on the people of Boston to return to the community. 
 
 "It has been refreshing to see the generous and at times heroic response to the Patriot's Day violence. Out challenge is to keep the spirit of community alive," he said. 
 
 Pictures of those killed were place on easels inside this cathedral and O'Malley said they live now in eternity. 
 
 At a Red Sox game on Saturday, fans filled Fenway Park with their voices, singing "The Star-Spangled Banner" in unison. 
 
 They applauded for law enforcement, they mourned the victims of the bombings and they showed their resilient spirit. 
 
 "We are one. We are strong. We are Boston. We are Boston strong," the announcer said to an eruption of cheers. 
 
 The Red Sox later pulled out a spirit-boosting win. 
 
 And America hasn't forgotten about David Henneberry, the man who tipped police off that Tsarnaev was hiding in his boat. 
 
 Bullets riddled the blood-stained vessel during a final volley of gunfire between Tsarnaev and law enforcement. Henneberry is being regarded as a hero, and people around the country are sending him checks to put toward a new boat. 
 
 Deborah Newberry, 62, of Orlando, Fla., told ABCNews.com she mailed a $25 check to Henneberry's home. 
 
 "Just listening to his coolness and how he handled the situation, it was like OK, that is a man who needs to have his boat restored," she said. 
 
 ABC News' Pierre Thomas, Anthony Castellano, Aaron Katersky and Christina Ng contributed to this report. ||||| The lone surviving suspect in the bombing attack on the Boston Marathon one week ago is communicating in writing, and could be ready to be questioned by an elite FBI team 
 
 As Boston prepared to mark with a moment of silence the passing of a week since the terror attack that killed three and wounded at least 176, Dzhokhar Tsarnaev was believed to be unable to speak but awake and responding to questions, possibly from medical staff. Tsarnaev is under heavy guard at Boston's Beth Israel Deaconess Medical Center, and is in serious condition with several injuries, including a possible gunshot wound to the neck. 
 
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 USA Today reported that the suspect began answering "substantive" questions from authorities Sunday night, but that could not be independently confirmed. If the interrogation has indeed begun, prosecutors may have just 48 hours before he must be read his Miranda rights and granted the right to remain silent and to have an attorney. White House spokesman Jay Carney said on Monday that Tsarnaev, who is a U.S. citizen, will be tried in civilian courts and not held as an enemy combatant. 
 
 Investigators believe the throat wound that left the 19-year-old suspect unable to speak may have been self-inflicted in a failed suicide bid that may have come as police closed in on him, as he hid inside a boat trailered in a backyard in Watertown, Mass., late Friday. 
 
 U.S. Senate Intelligence Committee member Dan Coats, R-Ind., told ABC Sunday the injuries may leave the suspect permanently unable to speak. 
 
 “The information we have is that there was a shot to the throat," Coats said. "And it’s questionable whether — when and whether -- he’ll be able to talk again.” 
 
 Meanwhile, Massachusetts Gov. Deval Patrick has asked residents to observe a moment of silence at 2:50 p.m. Monday, the time the first of two bombs exploded near the finish line. Bells will ring across the city and state afterward. 
 
 The most serious charge available to federal prosecutors would be the use of a weapon of mass destruction to kill people, which carries a possible death sentence. Massachusetts does not have the death penalty. 
 
 Davis also said Sunday authorities believe the suspects also were likely planning other attacks based on the cache of weapons uncovered during the Thursday night shootout, calling the stockpile "as dangerous as it gets in urban policing." 
 
 "We have reason to believe, based upon the evidence that was found at that scene -- the explosions, the explosive ordnance that was unexploded and the firepower that they had -- that they were going to attack other individuals," Davis said Sunday on CBS' "Face the Nation." "That's my belief at this point." 
 
 Davis added on "Fox News Sunday" that authorities cannot be positive there aren't more explosives that haven't been found, but the people of Boston are safe. 
 
 Also Sunday, a lawyer for the wife of Tamerlan Tsarnaev said federal authorities have asked to speak with his client as part of their investigation. 
 
 Authorities went to the suburban Rhode Island home of Tsarnaev's in-laws Sunday evening, where Katherine Russell Tsarnaev has been staying. Lawyer Amato DeLuca tells The Associated Press that she did not speak with them, and they are discussing how to proceed. 
 
 The twin bombings killed three people and wounded at least 176. 
 
 Patrick told NBC on Sunday that surveillance video clearly puts Dzhokhar Tsarnaev at the scene of the attack. 
 
 "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," Patrick said. "It's pretty clear about his involvement and pretty chilling, frankly. 
 
 According to media accounts, Tsarnaev and his brother, Tamerlan, were Muslims who recently gravitated to a radical strain of Islam, going so far as to post Anti-American, jihadist videos on social-media sites. Both are thought to have as-yet-unprobed ties to a radical Muslim cleric hellbent on the destruction of the American way of life. 
 
 A day-long dragnet for Tsarnaev ended Friday, with police capturing the suspect covered in blood and hiding in a boat in the backyard of a man who called 911 after becoming suspicious of activity on his property. 
 
 "We got him," Boston Mayor Tom Menino tweeted moments later, as neighbors gathered to form a gauntlet of cheers while a phalanx of police cars departed the scene. 
 
 Police moved in on Dzhokhar Tsarnaev Friday evening after a tip led them to the home on Franklin Street. 
 
 Neighbors said they heard more than 30 shots likened to "a roll of firecrackers shooting off." Police swarmed the scene, and several explosions, possibly police concussion grenades, were heard after a robot moved in on the boat. Less than two hours later, at about 9 p.m., the suspect, believed to have been injured in a wild shootout that spanned Thursday night to Friday morning, was being taken to Beth Israel Hospital. 
 
 No police were injured when shots were fired by the boat. 
 
 Sources told Fox News the shed and the boat had been searched earlier, but a local man noticed a door to it had been opened, saw blood on the tarp and called police. 
 
 "It was a call from a resident of Watertown," Watertown Police Chief Edward Deveau said. "We got that call, and we got the guy." 
 
 Davis said Tsarnaev was in serious condition and was found "covered with blood." He did not come out from inside the boat willingly, despite the efforts of negotiators, Davis said. 
 
 "We assume that those injuries came from the gunfire the night before," Davis said. 
 
 He also said Tsarnaev did not have any explosives with him when he was taken into custody. 
 
 "I, and I think all of the law enforcement officials, are hoping for a host of reasons the suspect survives," Patrick said after a ceremony at Fenway Park to honor the victims and survivors of the attack Saturday. "We have a million questions, and those questions need to be answered." 
 
 The hiding place was found just moments after police said their hunt for Tsarnaev, one of two radical Muslim brothers suspected in Monday's attack, had gone cold and urged people to "go about your business." 
 
 Shortly after the capture was announced, Watertown residents poured out of their homes and lined the streets to cheer police vehicles as they rolled away from the scene. 
 
 Celebratory bells rang from a church tower. Teenagers waved American flags. Drivers honked. Every time an emergency vehicle went by, people cheered loudly. 
 
 "Tonight, our family applauds the entire law enforcement community for a job well done, and trust that our justice system will now do its job," said the family of 8-year-old Martin Richard, who died in the bombing. 
 
 Early in the day, police told residents of several city neighborhoods, especially Watertown, to stay inside. School was canceled, bus and train service suspended and people were even told not to venture out for work. But those restrictions were lifted at the news briefing Friday night about 15 minutes before the gunshots were heard. 
 
 The boat Tsarnaev hid under was just outside the tight perimeter where Black Hawk helicopters patrolled the sky and police went door-to-door hunting for him, police said. Police say he and his older brother placed the deadly bombs, at least one of which was made from a pressure cooker packed with explosives and shrapnel, at the race, killing three and injuring more than 180. The sibling suspects are from Dagestan, a province in Russia that borders Chechnya, but have been in the U.S. for as much as a decade.. 
 
 On Thursday night, hours after the radicalized Muslims were fingered by the FBI and their images circulated around the world, they killed a Massachusetts Institute of Technology police officer and carjacked an SUV from a man who later escaped. The brothers led police on a chase through city streets that included a wild shootout that saw some 200 shots fired and the suspects hurling pipe bombs from the SUV. Bizarrely, police discounted earlier reports that the brothers had robbed a 7/11, saying although it had been robbed, and they had been caught on surveillance video, they were not the robbers. 
 
 The pursuit went into Watertown, where Tamerlan Tsarnaev, 26, was shot several times in the gunfight. But Dzhokhar Tsarnaev somehow slipped away, running over his already wounded brother as he fled by car, according to two law enforcement officials who spoke to The Associated Press on condition of anonymity. Tamerlan Tsarnaev was pronounced dead at Beth Israel Hospital Deaconess Medical Center Friday morning. But at some point following the shootout and car chase, the younger brother fled by foot, according to State Police, who said Friday night they don't believe he now has access to a car. 
 
 During the pursuit, a MBTA transit police officer was seriously injured and transported to the hospital, according to a news release. He was identified as Richard H. Donahue Jr., 33, and was at Mount Auburn Hospital in critical but stable condition. 
 
 The suspects' bloody rampage claimed the life of MIT Police Officer Sean Collier, 26, who was found shot to death in his squad car at 10:20 p.m. Thursday in what Davis termed a "vicious assassination." 
 
 Moments after the shooting, the brothers carjacked the Mercedes SUV from Third Street in Cambridge and forced the driver to stop at several bank machines to withdraw money. The driver later told police that the brothers had bragged to him that they were the marathon bombers, law enforcement authorities said. 
 
 “The guy was very lucky that they let him go,” Massachusetts State Police spokesman David Procopio said. 
 
 It was when police were working to activate the tracking device on the stolen SUV, that other patrol officers spotted it in nearby Watertown, touching off the dramatic chase. 
 
 FBI Special Agent Rick Deslauriers said Friday night the FBI pored though thousands of tips, and chased down countless leads in the intense probe following the terror attack on Monday. 
 
 "This was a truly intense investigation," Deslauriers said. "As a result of that, justice is being served for each of the victims of these crimes." 
 
 Click here for more from MyFoxBoston.com. 
 
 Fox News' Jennifer Griffin, Jana Winter, Mike Tobin, Mike Levine, Griff Jenkins and The Associated Press contributed to this report. ||||| Marathon bombing suspect Tamerlan Tsarnaev was alive and struggling with Watertown police early Friday morning, when his younger brother and alleged co-conspirator drove over him in a stolen SUV, dragging him on the pavement and apparently inflicting the fatal injuries that killed him, said Watertown Police Chief Ed Deveau in a Globe interview. 
 
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 Tsarnaev, 26, was pronounced dead early Friday morning at Beth Israel Deaconess Medical Center, after engaging police in ferocious firefight in Watertown. 
 
 His brother, Dzhokar Tsarnaev, 19, is in Beth Israel Deaconess Medical Center in serious condition. He was captured Friday night, after hiding for hours in a boat stored in a Watertown backyard. Authorities believe the brothers planted bombs made from pressure cookers at the finish line of the Boston Marathon on Monday, killing three and wounding more than 170. 
 
 The chief described the chain of events that led to Tamerlan Tsarnaev’s death, beginning late Thursday, after the brothers allegedly carjacked a man in Cambridge. The two brothers let the driver out unharmed, but the driver’s cellphone was still in his car, said Deveau. Police “pinged” the phone to determine where it was, he said, which alerted police that the suspects were in Watertown. 
 
 A local officer spotted the brothers driving in two cars, a Honda sedan and the stolen Mercedes SUV, said Deveau. The brothers stopped, jumped out and started firing on the officer, while more police rushed to the scene, he said. 
 
 “Quickly we had six Watertown police officers and two bad guys in a gunfight,” said Deveau. At least 200 shots were fired; maybe as many as 300, he said. 
 
 The shots, around 12:50 a.m., woke resident Jennings Aske, at 66 Laurel Ave. When he looked out his window he saw a green Honda Civic sedan stopped in the street, with its lights on and the driver’s side windows blown out. A husky man – apparently Tamerlan Tsarnaev—stood nearby firing a gun. 
 
 “I saw him standing there shooting at police,” Aske said. “When he fired, there was a little flash of light. I could hear the gun firing. It was terrifying.” 
 
 A police SUV came down Laurel Street, hearing west toward Dexter Ave., crashing into some trash cans on the sidewalk and into a parked car. Aske said he then saw a black Mercedes SUV drive up, also heading west toward Dexter Avenue. Then he heard two or three loud explosions, one of them large enough to shake the house. In an instant, the street “was crawling with police,” he said. 
 
 Deveau said the Tsarnaev brothers hurled something at the officers – apparently a pressure cooker bomb—and there was a tremendous explosion. Police later found the lid to a pressure cooker. “We believe it was an exact duplicate of the Boston Marathon bombs,” he said. The suspects also threw five “crude grenades” at officers; three of which exploded, he said. 
 
 One of his officers put his cruiser into gear and jumped out of it, letting it roll at the suspects to draw fire, he said. The suspects peppered the car with bullets. 
 
 After several minutes, the elder brother, Tamerlan, walked toward the officers, firing his gun until he appeared to run out of bullets, Deveau said. Officers tackled him and were trying to get handcuffs on him, when the stolen SUV came roaring at them, the younger brother at the wheel. The officers scattered and the SUV plowed over Tamerlan Tsarnaev, who was dragged briefly under the car, he said. 
 
 Dzhokar Tsarnaev abandoned the SUV almost immediately on a nearby street and fled on foot, triggering an all-day manhunt. 
 
 Meanwhile, officers at the scene treated MBTA Transit Police Officer Richard H. Donohue Jr., who had arrived on the scene and was wounded in the gunfight. 
 
 Aske continued to watch for several hours, while police searched the abandoned Civic with a robot, apparently looking for explosives. 
 
 The state medical examiner has not released an autopsy report detailing cause of death. ||||| BOSTON -- The suspected Boston Marathon bomber has begun responding to investigators in writing, a source familiar with the case said Sunday evening. 
 
 Dzhokhar Tsarnaev, 19, was in serious but stable condition at a Boston hospital, according to the FBI. He had been unable to speak due to a neck and throat injury, the source said. He was also intubated and breathing with the help of a respirator and earlier, officials had said he was not in any condition to be questioned. 
 
 It was not clear, however, whether what Tsarnaev was writing was of any value. 
 
 Authorities believe Tsarnaev may have tried to shoot himself before he was taken into custody Friday night because of the trajectory and location of the bullet wound in his neck, a source familiar with the investigation said Sunday. 
 
 The shot was fired at close range, the source said, suggesting the wound was self-inflicted. He was found hidden in a boat in a backyard in Watertown, Mass., bloody and injured. He was able to step out of the boat before being taken into custody after a brief exchange of gunfire with police and then negotiation with FBI agents, said Boston Police Commissioner Edward Davis. 
 
 As he lay on a stretcher in the back of an ambulance on the way to hospital, the suspect was mouthing curse words, either to himself or to the armed authorities standing watch in the ambulance as paramedics treated him, the source said. 
 
 Prosecutors in the case said Tsarnaev was not charged Sunday. 
 
 Asked by reporters whether charges would be filed against Tsarnaev Sunday, authorities released a statement saying, "There will be no press conference or further statement from the U.S. Attorney's Office this evening regarding the Boston Marathon attacks." 
 
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 Boston Mayor Thomas Menino said at the news conference that authorities are now convinced Tsarnaev and his brother, Tamerlan, who was killed in a shootout with police Friday morning, acted on their own in the bombing. 
 
 Davis said investigators also have found a circuit board with a wire slotted through it at the bombing scene on Boylston Street and the area had been swept clean of explosives. Menino said that area is still under the control of the FBI, but will be released to the city soon and a five-phase restoration is planned. 
 
 A source involved in the investigation said late Sunday the motorist carjacked by the two brothers as their rampage began last week said the young men stated they planned to drive to New York. The source called such a trip "extremely unlikely" given the extent of the manhunt for the suspects. That assessment was proved correct by the events that followed Friday. However, that tip prompted authorities in Connecticut to be on the lookout for the brothers. 
 
 Hundreds of FBI agents and other investigators have interviewed more than 100 people who knew the brothers, the source said. They are looking for any possible links to foreign extremists and seeking to understand how the plot developed and if anyone helped them, the source said. 
 
 He confirmed that Tamerlan Tsarnaev had video of a known jihadist on his YouTube channel, footage the source had viewed and characterized as "extremely inflammatory." 
 
 Menino had said earlier it has become clear that the older brother, Tamerlan, was the more influential, describing him as the "leader" and Dzhokhar as a "follower." 
 
 "His [older] brother read those magazines that are published on how to create bombs," Menino said. 
 
 Investigators are also tracking the brothers' online activities, phone calls and text messages, examining hundreds of pieces of evidence -- including bomb components, unexploded devices as well as the brothers' vehicles, guns, and financial records seized from various sites across Boston and surrounding suburbs, authorities said. 
 
 The blasts set off near the finish line of the marathon killed three people and injured more than 180. 
 
 Sunday morning, Davis said on the CBS News show, "Face the Nation" that the crime scene from the early Friday morning firefight in Watertown, Mass., that killed Tamerlan Tsarnaev was "littered" with unexploded improvised explosive devices. 
 
 Davis said it's his belief that the brothers were "going to attack other individuals" -- and Davis said that's based on the evidence at the scene and the firepower that the brothers had. 
 
 Two men with connections to the brothers were taken into custody Saturday in New Bedford, Mass., and eventually arrested and detained on immigration violations by Immigration and Customs Enforcement, that agency announced. 
 
 The source said those arrests were made in an abundance of caution because the men were friends and former roommates of Dzhokhar Tsarnaev and had regular contact with him. Officials want to question them at greater length about whether they knew anything about the brothers' plans or provided any help to them. 
 
 Sunday morning, Boston Cardinal Sean O'Malley implored hundreds of parishioners at a Mass at the Cathedral of the Holy Cross to forgive the suspected Boston Marathon bombers and seize on the goodwill born of the tragedy. 
 
 "We must be people of reconciliation -- not revenge," he told about 800 parishioners during a service that honored four killed in last week's marathon bombings and their aftermath. Candles lighted an altar with photos of the dead victims, including the three killed Monday in the bombing, and a police officer killed Friday in a shootout. 
 
 Speaking to reporters after the Mass, O'Malley reiterated the church's opposition to the death penalty. "Forgiveness does not mean that we do not realize the heinousness of the crime. But in our hearts, when we are unable to forgive, we make ourselves a victim of our hatred. Forgiveness is part of our obligation of disciples of the Lord." 
 
 Also Sunday, Massachusetts Gov. Deval Patrick said on NBC's "Meet the Press" that video footage clearly shows Dzhokhar Tsarnaev placing a backpack near the marathon finish line. 
 
 "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," Patrick said. "It's pretty clear about his involvement and pretty chilling, frankly." 
 
 Patrick said it's hard to imagine why someone would deliberately harm "innocent men, women and children in the way that these two fellows did." 
 
 The FBI had disclosed this week that it had questioned Tamerlan Tsarnaev in 2011 regarding possible terrorist connections, but found nothing and took no action against him. 
 
 Sen. Charles Schumer (D-N.Y.) said Sunday he understood that the FBI didn't find any troubling evidence during its initial contact with the suspect in 2011 -- prompted by concerns passed along by Russian authorities -- but he noted that was before Tamerlan Tsarnaev made a suspicious overseas trip. 
 
 "Then he went to Russia and he came back and almost immediately put very radical things on his website," Schumer said of the elder Boston bombing suspect. "Why didn't the FBI, having known that he was someone a foreign government at least thought might be dangerous, go interview him again?" 
 
 Schumer, speaking during an unrelated news conference, said that the federal death penalty law he helped co-author in the 1990s would be "appropriate" in the case of surviving suspect Dzhokhar Tsarnaev. 
 
 On Saturday, Rep. Peter King (R-Seaford) had also questioned the FBI's actions. 
 
 Meanwhile, rebels in Russia's North Caucasus region denied any link to the April 15 attack on the Boston Marathon in a statement posted on the vdagestan.com website. 
 
 "The Caucasian Mujahedeen are not fighting with the United States of America," according to the statement, which was attributed to unidentified Mujahedeen commanders in Dagestan. "We are at war with Russia, which is responsible not only for the occupation of the Caucasus, but also for heinous crimes against Muslims." 
 
 An FBI-led probe is looking into a six-month trip suspect Tamerlan Tsarnaev, an immigrant of Chechen descent, took around two years ago to Chechnya and neighboring Dagestan, both regions of Russia that have been embroiled in Islamist separatist movements. 
 
 In Medford, Mass., relatives and friends were expected to attend a viewing Sunday for marathon bombing victim Krystle Campbell, 29, at the Dello Russo Funeral Home, 306 Main St. from 3 to 7 p.m. On Monday at 10 a.m., there will be a procession from the funeral home to St. Joseph Church for a Mass of Christian Burial at 11 a.m. Services will conclude with burial at Oak Grove Cemetery. 
 
 The Associated Press reported that doctors said the Boston transit police officer wounded in a shootout with the bombing suspects had lost nearly all his blood and his heart had stopped from a single gunshot wound that severed three major blood vessels in his right thigh. 
 
 Surgeons at Mount Auburn Hospital in Cambridge say Richard Donohue, 33, is in stable but critical condition. He is sedated and on a breathing machine but opened his eyes, moved his hands and feet, and squeezed his wife's hand Sunday. 
 
 Emergency workers started CPR on the scene to restart his heart. Doctors say he is expected to make a full recovery and that nerves and muscles in his leg are intact. 
 
 Transit officials say Donohue had gotten out of his cruiser and was shooting at the suspects when he was hit late Thursday night in a gun battle in Cambridge. 
 
 "He went in there and engaged people who were shooting at his fellow officers," Donohue's brother, Edward, said at a news conference Sunday at the hospital. "I cannot describe the pride I have," said the younger Donohue, who is a patrolman for the Winchester Police Department. 
 
 The fellow officers included a friend, MIT police officer Sean Collier, who authorities say was shot to death at the beginning of the brothers' rampage earlier in the night. 
 
 Richard Donohue has been a transit officer for three years, said Paul MacMillan, chief of the Massachusetts Bay Transportation Authority. 
 
 The University of Massachusetts-Dartmouth, where Dzhokhar Tsarnaev was a student, reopened Sunday at noon, university officials announced on the school's website. 
 
 With Nicole Fuller, 
 
 Paul LaRocco and 
 
 The Associated Press
– Dzhokhar Tsarnaev has regained consciousness and has been giving investigators written answers to questions, law enforcement sources tell ABC, though it's unclear if he's actually saying anything useful yet. Sources tell Fox News that he will not be formally charged today. The Boston bombing suspect is listed as in serious but stable condition at the Beth Israel Deaconess Medical Center, with neck and throat injuries that prevent him from talking. The shot that injured his throat was fired at close range, sources tell Newsday, and that, combined with the bullet's apparent trajectory, leads investigators to believe that the 19-year-old shot himself in a failed suicide attempt after police discovered his hiding place. The source says Tsarnaev was mouthing curse words as an ambulance rushed him to the hospital, though it's unclear if they were aimed at his doctors, his captors, or himself. Investigators now believe Dzhokhar may have dealt the killing blow to his brother, Tamerlan, the Boston Globe reports. The 26-year-old had apparently run out of bullets and was struggling with police officers trying to handcuff him when his younger brother sped toward them in a stolen SUV, causing officers to scatter and running over the elder brother, who was briefly dragged by the vehicle, Watertown's chief of police says.