Boston authorities say they have shot and killed "Suspect 1" in the Boston Marathon bombing while "Suspect 2" is on the run after a series of violent events in Watertown, Mass.

Now, according to MSNBC's Chuck Todd, police believe they know where "Suspect 2" "is holed up."

Live feeds show police outside a house in Watertown, with SWAT teams telling someone inside a house to come out. Police clearly have their guns drawn, but there are reports that the house may be "booby-trapped," according to NBC News. Journalists are being repeatedly ordered to get back.

A national security official has confirmed to Reuters the name of the "Suspect 2" is Dzhokhar A. Tsarnaev, 19, of Cambridge, Mass., and "Suspect 1" is his 26-year-old brother Tamerlan Tsarnaev.

Police now believe that more people may be involved, according to NBC's Pete Williams. He said this afternoon that the city's lockdown status may be the result of police believing that the "marathon bombing is the work of more than just two people." But police said later that the focus is solely on Dzhokhar Tsarnaev.

NBC reported Friday afternoon that police have recovered seven IEDs in their search:

MORE: 7 IEDs recovered in the searches so far, some in Watertown & some at the house in Cambridge, police officials say — NBC Nightly News (@nbcnightlynews) April 19, 2013

The Associated Press reports that both of the identified suspects are from the Russian region near Chechnya. Their father, uncle, and aunt have given interviews to the press.

UMASS Dartmouth has confirmed that one suspect was a student. The campus is now on lockdown.

SWAT teams were going house to house in a 20-block area of Watertown. All morning the Massachusetts State Police Bomb Squad has been collecting and disposing of several explosive devices presumably placed by the suspects.

CNBC is also reporting that two people are in custody at a house on Norfolk St. Watertown. It is not clear at present who these two people are.

At a press conference this morning, Gov. Deval Patrick said that the entire area of Boston was on lockdown, though in areas this appears to have been eased. Police are telling residents to stay inside and businesses not to open until further notice.

Patrick reiterated that this afternoon, telling residents to lock their doors. Between 60-70% of Cambridge homes have been swept.

State police said there will be a controlled explosion in Cambridge, Mass., this afternoon, out of an abundance of caution.

Classes are cancelled at all area colleges and public schools.



All Massachusetts Bay Transpiration Authority (MBTA) service has been suspended. Vehicle traffic in and out of Watertown has been suspended. Taxi service was also suspended for a time.

Police are calling for armored vehicles to a specific intersection. This while busloads of residents being evacuated nearby. — Doug Saunders (@DougSaunders) April 19, 2013

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

The dramatic turn of events began Thursday night with a robbery at a convenience store — reports that state police have now denied — where "Suspect 2" was ID'd by police. That was followed by a fatal shooting of an MIT police officer at about 10:30 p.m. in Cambridge, Mass. The MIT officer has been named by the Boston Globe as Sean Collier, 26, of Somerville.



Police say the suspects then committed an armed carjacking in Cambridge. When police pursued them into neighboring Watertown, the suspects threw explosive devices out of the stolen car.

The suspects then began shooting. Police returned fire and eventually killed "Suspect 1" (who reportedly had a bomb strapped to his chest). An MBTA police officer, later named as 33-year-old Richard H. Donohue Jr, was seriously injured in the exchange.

The Boston Globe reports that their sources say "an explosive trigger was found" on Suspect 1's body.

"Suspect 2," who is considered "armed and dangerous," then drove away and abandoned the car. He's been at large ever since. There has been speculation on the Boston PD scanner that he may be wearing a suicide vest.



Here's a graphic organizing the series of violent events on Thursday night and Friday morning:





And here's a map of the key events:

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