[NEWER UPDATES ON TOP]

6:24PM EDT: Stay indoors request lifted, public transit service restored in Boston, authorities say. However, Boston bombing suspect Dzhokar Tsarnaev remains at large, Col. Timothy Alben, of the Massachusetts State Police said.

4:38PM EDT: Seven IEDs recovered so far—in Watertown & some at house in Cambridge, police officials tell NBC.

3:45PM EDT: CBS: Suspects had built number of bombs, including pipe bombs. pipe bombs discovered.

3:53PM EDT: Honda mini van & Honda CRV just towed away from Boston bombing suspect’s home in Cambridge.

3:48PM EDT: Mass. State Police: “investigators recovering significant amount of homemade explosives. No proof yet of accomplices”.

3:20PM EDT: The FBI has removed a computer from the New Jersey home of the sister of the Boston Marathon bombing suspects. Police in West New York say the woman is cooperating in the investigation, but they didn’t immediately release her name.

2:40PM EDT: The aunt of the suspected Boston bomber claimed Friday afternoon on CNN that her nephew Dzhokhar Tsarnaev was framed for the attack. “I’m suspicious that this was staged,” Maret Tsarnaev said from Toronto, Canada. Asked who she believes framed them and why, she responded, “Whoever needs this. Whoever is looking for those who need to be blamed for these attacks.”

2:33PM EDT: ABC News quoting a source saying suspect #2 was likely wounded in the firefight last night; likely has ‘suicide vest’ now.

1:13PM EDT: (AP) The FBI is at the northern New Jersey home of the sister of the Boston Marathon bombing suspects. The police director in West New York, N.J., says the woman has told authorities she has not been in frequent touch with her brothers. He says she is very upset. Police did not have her name. They have cordoned off the three-story brick building across the Hudson River from New York City. The woman, speaking through a crack in the door, tells The Star-Ledger of Newark her brothers are smart and great people. She says she doesn’t know what got into them.

She also tells the newspaper she is sorry for “all the people who are hurt.”

12:40PM EDT: Mass. State Police Superintendent: New leads have developed, updates within an hour.

12:39PM EDT: State Police warns they will do a controlled explosion of items found in Norfolk Street in Cambridge where the brothers lived.

12:34PM EDT: Mass. Gov. Patrick is giving a press conference now. He says “stay indoors” request is still in place and developments continue.

12:32PM EDT: News conference just started.

12:21PM EDT: Military Blackhawk helicopters landing in Watertown.

11:38AM EDT: Bombing suspect at large became U.S. citizen on Sept. 11, 2012.

11:06AM EDT: (Reuters) President Barack Obama was briefed by his top security and counter-terrorism advisers on developments in the Boston bombing manhunt and investigation for about an hour in the White House Situation Room on Friday, the White House said. The briefing ended just shortly after 10:45 a.m. EDT, the White House said.

10:54AM EDT: Media being ordered on to the ground during police situation in Watertown, Mass

10:50AM EDT: Police are detaining someone, they have him handcuffed and he is on his back, dispatch audio says.

10:48AM EDT: Just now, NBC reporting that officers sought cover, a man may be down in Watertown.

10:47AM EDT: CNN is showing live footage from Watertown, of police with guns drawn. Reporters are being asked to stay back and get down.

YWN PHOTO LINK: Click HERE for photos from Boston.

10:45AM EDT: (Reuters) A car sought by Connecticut State Police and believed to be occupied by a possible suspect linked to the Boston Marathon bombing has been located in the Boston area, a police spokesman said on Friday.

10:14AM EDT: American Airlines implements travel change policy for customers going to Logan Airport today. Call AA 1-800-433-7300

9:41PM EDT: ABC News: Father of bombers spoke to them yesterday. He was worried they were hurt, they told him they were ok.

9:30AM EDT: (AP) Transportation to and from the Boston area is virtually shut down Friday morning, with the exception of airplanes, which continue to take off and land at Logan International Airport.

Amtrak has stopped trains about an hour south of the city in Providence, R.I. The Massachusetts Bay Transportation Authority, which operates commuter trains into Boston as well as the city’s subway — called the T — and the city’s buses suspended all operations.

JetBlue, the largest airline in Boston, is allowing anybody scheduled to fly to or from Boston to change their ticket for free.

Megabus has canceled at least 18 buses between Boston and New York, New Haven, Conn., Hartford, Conn., Burlington, Vt. and Philadelphia.

9:00AM EDT: As per Boston PD, the suspect has just posted on the Internet (unknown where) “‘I WILL KILL ALL OF YOU, YOU KILLED MY BROTHER”.

8:42AM EDT: Police with guns drawn: “If you’re in the house come out.”

8:36AM EDT: Officers converging on Quimby Street and Willow street , guns drawn Military Police now pushing crowd back.

8:27AM EDT: DEVELOPING: Heavy police activity in #Watertown near wooded area. Officers crouched behind vehicles, guns drawn. #7News

8:02AM EDT: The entire city of Boston is on lockdown; officials asking public to stay put, hunker down, and don’t open their doors.

7:54AM EDT: (Reuters) The Federal Aviation Administration closed airspace over a 7-mile-wide (11 km) stretch of the northwest Boston area on Friday to provide a “safe environment for law-enforcement activities” as police searched for a second Boston Marathon bomb suspect.

The restriction, which echoes similar measures imposed after Monday’s bombing, applies to all aircraft flying below 3,000 feet (914 metres), according to an FAA bulletin.

There were no immediate reports of restrictions at Boston’s Logan airport.

7:00AM EDT: (AP) A law enforcement intelligence bulletin obtained by the AP identified the surviving bomb suspect as Dzhokhar A. Tsarnaev, 19, of Cambridge, Mass. Two law enforcement officials told AP that Tsarnaev and the other suspect who was not immediately identified have been living legally in the U.S. for at least one year.

Russia’s North Caucasus region has been plagued by an Islamic insurgency stemming from separatist wars in Chechnya.

6:40AM EDT: AP sources:  Boston bomb suspects from Russia region near Chechnya, lived in US at least 1 year.

6:20AM EDT: Intense scanner traffic right now…officer has detained 3 people in a cab near Watertown, crews rushing to scene. Possibly have second suspect in custody…not confirmed…DEVELOPING

6:12AM EDT: U.S. President Barack Obama was briefed overnight by a counter terrorism aide on the Boston bombing investigation and manhunt, a White House official said on Friday.

6:05AM EDT: (AP) Police are locking down some neighborhoods in Boston and its western suburbs as they search for the remaining suspect in the marathon bombings. Authorities urged residents in Watertown, Newton, Waltham, Belmont, Cambridge and the Allston-Brighton neighborhoods of Boston to stay indoors.

6:03AM EDT: (Reuters) Boston police said on Friday that all transit service by the Massachusetts Bay Transportation Authority “has been suspended until further notice” as a manhunt for a suspect in the bombing of the Boston Marathon was ongoing in a city suburb.

5:53AM EDT: The Massachusetts Governor has suspended all public transportation; commuters told to ‘stay home, stay indoors.’

5:51AM EDT: (AP) Doctors at a Boston hospital where a suspect in the marathon bombings was taken and later died are saying they treated a man with a possible blast injury and multiple gunshot wounds.

Doctors and officials at Beth Israel Deaconess Medical Center wouldn’t say if the patient they treated, who came in with police, was the suspect in the black hat from marathon surveillance footage.

Authorities say one bombing suspect was still on the loose following a shootout during which explosives were thrown at police. Residents of Watertown, just outside Boston, were told to stay in their homes.

An emergency room doctor says he heard gunshots near his home in Watertown and knew he needed to get back to the hospital.

Doctors and hospital officials say they don’t have any information on the identity of deceased patient.

5:44AM EDT: President Obama has been briefed of the unfolding situation.

5:08AM EDT: Hospital say marathon bombing suspect was brought in in “traumatic arrest;” pronounced dead at 1:35am local time.

4:55AM EDT: (Reuters) Police in Watertown, Massachusetts, are looking for a suspect in the Boston Marathon bombing, officials said early on Friday.

“We believe this to be a terrorist. We believe this to be a man who has come here to kill people. We need to get him in custody,” said Boston Police Commissioner Edward Davis.

The suspect police are looking for in Watertown is the one seen in images released by the FBI of a man wearing a white cap, Davis said.

The other suspect in those images was killed during a pursuit by officers, police said.

4:45AM EDT: (AP) Police say one of two suspects in the shooting of a Massachusetts Institute of Technology police officer is dead and a massive manhunt is underway for another, who is believed to be tied to the Boston Marathon bombing.

Shortly after the MIT officer was shot dead Thursday night, police got a report of a carjacking in Cambridge, just outside Boston. One of the two suspects in that officer’s shooting was killed. Police say of the at-large suspect, “We believe this to be a terrorist.”

The FBI said it is working with local authorities to determine what happened.

The MIT shooting on the Cambridge campus Thursday night was followed by reports of violence in nearby Watertown, about 10 miles west of Boston.

State police spokesman David Procopio had said there was a “strong possibility” the incidents are related.

The MIT officer had been responding to report of a disturbance Thursday night when he was shot multiple times, according to a statement from the Middlesex district attorney’s office and Cambridge police. It said there were no other victims.

In Watertown, witnesses reported hearing multiple gunshots and explosions at about 1 a.m. Friday. Dozens of police officers and FBI agents were in the neighborhood and a helicopter circled overhead.

State police spokesman David Procopio said, “The incident in Watertown did involve what we believe to be explosive devices possibly, potentially, being used against the police officers.”

Boston cab driver Imran Saif said he was standing on a street corner at a police barricade across from a diner when he heard an explosion.

“I heard a loud boom and then a rapid succession of pop, pop, pop,” he said. “It sounded like automatic weapons. And then I heard the second explosion.”

He said he could smell something burning and advanced to check it out but area residents at their windows yelled at him, “Hey, it’s gunfire! Don’t go that way!”

MIT said right after the 10:30 p.m. shooting that police were sweeping the campus in Cambridge and urged people to remain indoors. They urged people urged to stay away from the Stata Building, a mixed-use building with faculty offices, classrooms and a common area.

Hours later, MIT, which has about 11,000 students, said the campus was clear but the shooter was still on the loose.

3:10AM EDT: (Reuters) Massachusetts State Police warned people in the Boston suburb of Watertown not to open their doors and said they would conduct a door-to-door, street-by-street search due to what it called a fluid situation.

It was not immediately clear what connection the warning may have to the Boston Marathon bombings.

A massive police operation was under way in Watertown after a university police officer at the Massachusetts Institute of Technology was killed and one man was taken into custody in Watertown.

2:55AM EDT: (Reuters) Police descended on a Boston suburb amid reports of gunfire and explosions shortly after a university police officer was shot dead on the MIT campus Thursday night, touching off a manhunt in a community on edge just days after the Boston Marathon bombing.

Neighbors reported hearing several gunshots and explosions in Watertown, a neighboring suburb to the Massachusetts Institute of Technology where the campus police officer was killed.

At least one suspect was in police custody from the Watertown incident, the ABC TV station in Boston reported. Reuters was not immediately able to verify the reports.

It was not clear if the police activity in Watertown was related to the shooting at MIT, or if either was connected to the bombing of the Boston marathon, which killed three people and wounded 176.

Investigators released pictures and video of two suspects in the Boston Marathon bombing on Thursday, enlisting the public’s help in identifying two men wearing backpacks and baseball caps in the crowd minutes before bombs exploded near the finish line.

Police officers with weapons drawn, and people wearing FBI and ATF jackets could be seen in the live video and long afterward police continued to call the scene active.

Boston police called it an “active incident” ongoing in Watertown and urged residents to remain inside.

Rebecca Carbone, 30, stood on the street wearing pajamas and a sweatshirt and had stepped out when she heard sirens.

“We heard a loud blast and we didn’t know what it was,” Carbone said. “It sounded like a car backfiring.”

John Grimes, 69, a retired letter carrier, said that he heard three loud explosions, “and you don’t hear explosions at night a lot.”

MIT early on Friday said MIT police had determined that the suspect in the shooting was no longer on campus and it was now safe to resume normal activities.

David Procopio, a spokesman for the Massachusetts State Police, said late on Thursday the motive for the shooting was not known and the investigation would be led by the Middlesex County District Attorney’s Office after the death of the officer.

Procopio said he could not “say that with 100 percent certainty at this time” that the shooting at the MIT campus was not related to the Boston Marathon bombing. He could not be reached for comment after the Watertown incident.

FBI Boston Special Agent Greg Comcowich said the office was referring questions about the MIT shooting to Cambridge and MIT police. “I can tell you that we are aware of it however.”

MIT police representatives could not be reached immediately for comment.

(YWN World Headquarters – NYC)