LIVE Coverage from WHDH Boston

Click here for more photos from the manhunt

BOSTON—A 19-year-old suspected bomber has so far eluded capture after fleeing from police on foot in the Watertown suburb of Boston Friday night.

Thousands of law enforcement officers finished a nearly 24-hour door-to-door manhunt for the suspect, Dzhokhar A. Tsarnaev, in Monday's Boston Marathon bombings that wounded more than 170 people and left three dead. Officials announced at 6:00 p.m. that they were unable to apprehend the suspect, despite combing through a 20-block area of the Boston suburb of Watertown and shutting down the city's entire public transportation system in an effort to prevent him from fleeing.

Gov. Deval Patrick lifted his previous "shelter in place" order for the city of Boston and many surrounding areas of the city. But Patrick urged Bostonians to continue to be "vigilant" as the "very dangerous" armed and dangerous suspect has not been apprehended.

"We cannot continue to lock down an entire city or an entire state," Massachusetts State Police Col. Timothy Alben said. He added that he believes the suspect is still in the state.

A late-night police chase and shootout left one marathon bombing suspect—26-year-old Tamerlan Tsarnaev—dead and the other, his younger brother, Dzhokhar, on the lam. One police officer was killed and another seriously wounded during the violent spree. The city of Boston and its surrounding areas ground to a standstill for hours as police went door to door searching for the suspect in the suburb of Watertown.

NBC News reported that police uncovered seven improvised explosive devices (IEDs) in Watertown and in the brothers' home in Cambridge.

The suspect on the run is a student at the University of Massachusetts Dartmouth. He and his brother's family is originally from Chechnya, a volatile and once war-torn southern Russian republic. The family fled to Kyrgyzstan and eventually immigrated to the United States as refugees about 10 years ago.

His older brother studied at a local community college and was a Golden Gloves boxer. Tamerlan Tsarnaev also reportedly had a wife and young child. Dzhokhar Tsarnaev, who was remembered by former classmates as bright and personable, posted links to pro-Chechnyan independence sites on his social media page, and listed his world view as "Islam." It's unclear if either the separatist politics of Chechnya or their religion had anything to do with the suspects' motivations.

Tsarnaev appeared to be posting to his Twitter account even after the attacks, writing in his last post on Wednesday, "I'm a stress free kind of guy." His posts covered everything from cute photos of his cat to rap lyrics. In an interview with The New York Times, the suspects' father said Tamerlan was unable to become a U.S. citizen because he was arrested for hitting his girlfriend, and that he traveled to Russia last year to live for six months and renew his passport.

The suspects' uncle, when told that one of his nephews was killed by the local CBS News station, replied that he deserved it. “He deserved his. He absolutely deserved his,” Ruslan Tsarni said. “They do not deserve to live on this earth.”

In an emotional press conference, Tsarni said his nephews had brought shame upon his family, and called them "losers." He said they were not "able to settle themselves" and were "angry at everyone who was able to." He said he did not believe they were motivated by radical politics in Chechnya or their Muslim religion.

"Dzhokhar, If you're alive, turn yourself in and ask for forgiveness from the victims [and] the injured," he said. "He put a shame on our family. He put a shame on the entire Chechnyan ethnicity. Turn yourself in."

He added that he hadn't been in touch with the family for several years but would not say why.

"I'm ready to kneel in front of them and ask their forgiveness," Tsarni said of the victims of his nephews' crime. "I respect this country; I love this country ... this country that gives everybody chance to be treated like human being."

The University of Massachusetts at Dartmouth announced shortly after 10:30 a.m. on Friday that they were evacuating the entire campus after learning Tsarnaev is a registered student there.

Earlier, at sunrise, Gov. Patrick ordered a shutdown of all public transit and for residents in the city of Boston and on its edges to stay indoors as a massive manhunt for the second suspect was underway. Police focused on a 20-block area of Watertown and said they feared the suspect could be wearing explosives. Amtrak also shut down all trains between Boston and New York.

“This situation is grave and we are trying to protect the public safety,” said Alben, who ordered a lockdown of Watertown, Waltham, Belmont, Cambridge, Newton, Allston and Brighton. Brookline was later ordered to be on lockdown as well. A no-fly zone has been declared over Watertown. The city of Boston was eerily quiet during Friday's rush hour, the city's busy intersections totally abandoned.

The mayhem began at approximately 10:20 p.m. Thursday in Cambridge when police said the bombing suspects shot and killed an MIT campus officer, Sean Collier, 26. The terror suspects then carjacked a Mercedes-Benz SUV with the driver inside and fled, eventually letting the driver go.

The suspects were then spotted in Watertown, where federal agents swarmed in. At approximately 3:30 a.m., Massachusetts State 

Police issued a plea on Twitter for residents of Watertown to lock their doors and not open them for anyone, as dozens of police officers, many of them off duty, searched backyards and exteriors of houses there, and a police perimeter of several blocks was established.

Worried residents were also told to turn off their cell phones out of fear that they could trigger improvised explosive devices.

The suspects exchanged dozens of rounds of gunfire with patrol officers, and lobbed IEDs out of their vehicle, injuring several officers.

Tamerlan Tsarnaev was shot by police and brought to Beth Israel Medical Center. He arrived at the hospital under cardiac arrest with multiple gunshot wounds and blast-like injuries to his chest. The second suspect fled on foot, leading to the tense manhunt that is still underway at this hour. The Boston Globe reported that he ran over his own brother when fleeing, but Alben did not confirm that at Friday's press conference.

A transit police officer, Richard H. Donohue, was seriously wounded during the exchange of gunfire, officials said.

K9 units and SWAT teams searched homes on Spruce Street as officers with a police robot searched an SUV that the suspects had abandoned. Multiple devices were left in the road and two handguns were recovered, according to police scanners.

"We believe this to be a terrorist," said Boston Police Commissioner Ed Davis, of Tsarnaev. "We believe this to be a man who has come here to kill people. We need to get him into custody."

[Related: FBI releases photos of suspects in Boston Marathon bombings]

In a radio alert issued issued to fellow officers, the suspect was described as a "white male with dark complexion ... with thick curly hair wearing a charcoal gray hooded sweatshirt ... possibly with an assault rifle and explosives."

Police in Watertown, Newton, Brighton and Cambridge were put on high alert. "Units use caution," an officer said. "He might have an explosive object on his person."