Manhunt for Boston bombing suspects

Police in tactical gear conduct a search for Dzhokhar A. Tsarnaev in Watertown, Mass., April 19, 2013.

After a car chase and shoot out with police, one suspect in the Boston Marathon bombing, Tamerlan Tsarnaev, 26, was shot and killed by police early morning April 19, and a manhunt is underway for his brother and second suspect, 19-year-old suspect Dzhokhar A. Tsarnaev. The two men, reportedly Chechen in origin, are suspects in the bombings at the Boston Marathon on April 15, that killed three people and wounded at least 170.

A police officer runs with his weapon drawn as he conduct a search for a suspect in the Boston Marathon bombings in Watertown, Mass., April 19, 2013.

Police in tactical gear seen outside a home in Watertown, Mass., April 19, 2013.

A woman reacts while being questioned by the Cambridge Police and other law enforcement agencies in Watertown, Mass., April 19, 2013.

SWAT team members search for Dzhokhar A. Tsarnaev at a residential building in Watertown, Mass., as a man looks out from a window, April 19, 2013

A police officer evacuates a shoeless man holding a child as members of law enforcement conduct a search for Dzhokhar Tsarnaev, in Watertown, Mass., Friday, April 19, 2013.

Members of the FBI, State Police, Boston Police, Cambridge Police, and other law enforcement agencies, survey the perimeter near the home of Dzhokhar A. Tsarnaev on Norfolk Street in Watertown, Mass., April 19, 2013.

Police officers aim their weapons Friday, April 19, 2013, in Watertown, Mass. A tense night of police activity that left a university officer dead on campus just days after the Boston Marathon bombings and amid a hunt for two suspects caused officers to converge on a neighborhood outside Boston, where residents heard gunfire and explosions.

Members of law enforcement agencies, survey the perimeter near the home of Dzhokhar A. Tsarnaev in Watertown, Mass., April 19, 2013.

Members of the FBI, State Police, Boston Police, Cambridge Police, and other law enforcement agencies, survey the perimeter in Watertown, Mass., April 19, 2013.

Members of the FBI, State Police, Boston Police, Cambridge Police, and other law enforcement agencies, survey the perimeter near the home of Dzhokhar A. Tsarnaev on Norfolk Street in Watertown, Mass., April 19, 2013.

A barefooted woman runs for cover as police surround a home while searching for a suspect in the Boston Marathon bombings in Watertown, Mass., April 19, 2013.

A neighbor is escorted to safety as police surround a home while searching for a suspect in the Boston Marathon bombings in Watertown, Mass., April 19, 2013.

WATERTOWN, MA - APRIL 19: A Boston SWAT team member takes up as posistion as they search for 19-year-old bombing suspect Dzhokhar A. Tsarnaev on April 19, 2013 in Watertown, Massachusetts. After a car chase and shoot out with police, one suspect in the Bo — Mario Tama/Getty Images

A Boston SWAT team member takes up as position as they search for 19-year-old bombing suspect Dzhokhar A. Tsarnaev, April 19, 2013 in Watertown, Massachusetts.

Residents take pictures and look on as members law enforcement agencies, survey the perimeter in Watertown, Mass., April 19, 2013.

A Massachusetts State Police officer checks the bag of a cyclist during heightened security in Watertown, Mass., April 19, 2013.

Metro SWAT members hang off the back of a truck as they prepare to search the School and Walnut Street neighborhood for one remaining suspect on April 19, 2013 in Watertown, Massachusetts.

Police on School and Walnut Street on April 19, 2013 in Watertown, Massachusetts. Earlier, a Massachusetts Institute of Technology campus police officer was shot and killed at the school's campus in Cambridge.

Two suspects in the Boston Marathon bombing killed an MIT police officer, injured a transit officer in a firefight and threw explosive devices at police during their getaway attempt in a long night of violence that left one of them dead and another still at large Friday, authorities said as the manhunt intensified for a young man described as a dangerous terrorist.

Members of the FBI, State Police, Boston Police, Cambridge Police, and other law enforcement agencies, survey the perimeter near the home of Dzhokhar A. Tsarnaev, Watertown, Mass., April 19, 2013., Mass., April 19, 2013.

With his weapon drawn, an official inspects an apartment building in Watertown, Mass., April 19, 2013.

An official wearing tactical gear, left, looks on as others enter an apartment building in Watertown, Mass., April 19, 2013.

This surveillance photo released via Twitter Friday, April 19, 2013 by the Boston Police Department shows a suspect that police are pursuing in Watertown, Mass., entering a convenience store.

The suspects were identified to The Associated Press as coming from the Russian region near Chechnya, which has been plagued by an Islamic insurgency stemming from separatist wars. A law enforcement intelligence bulletin obtained by the AP identified the surviving bomb suspect as Dzhokhar A. Tsarnaev, a 19-year-old who had been living in Cambridge, just outside Boston, and said he "may be armed and dangerous."

Members of the FBI, State Police, Boston Police, Cambridge Police, and other law enforcement agencies, survey the perimeter near the home of Dzhokhar A. Tsarnaev,Watertown, Mass., April 19, 2013.

Military Police arrive in armored vehicles at the parking lot of the Arsenal Mall on April 19, 2013 in Watertown, Massachusetts.

Authorities said surveillance tape recorded late Thursday showed the suspect known for the white hat during a robbery of a convenience store in Cambridge, near the campus of MIT, where a university police officer was killed while responding to a report of a disturbance, said State Police Col Timothy Alben. The officer died of multiple gunshot wounds.

From there, authorities say, the two men carjacked a man in a Mercedes-Benz, keeping him with them in the car for half an hour before releasing him at a gas station in Cambridge. The man was not injured. The search for the vehicle led to a chase that ended in Watertown, where authorities said the suspects threw explosive devices from the car and exchanged gunfire with police. A transit police officer was seriously injured during the chase, authorities said.

Police officers walk near a crime scene Friday, April 19, 2013, in Watertown, Mass. A tense night of police activity that left a university officer dead on campus just days after the Boston Marathon bombings and amid a hunt for two suspects caused officers to converge on a neighborhood outside Boston, where residents heard gunfire and explosions.

Police descend on School and Walnut Street chasing possible suspects on April 19, 2013 in Watertown, Massachusetts. Earlier, a Massachusetts Institute of Technology campus police officer was shot and killed at the school's campus in Cambridge. A short time later, police reported exchanging gunfire with alleged carjackers in Watertown, a city near Cambridge.

A police officer rides on the back of a van at a staging area as a manhunt is conducted for a suspect Friday, April 19, 2013, in Watertown, Mass. One of two suspects in the Boston Marathon bombing is dead and a massive manhunt is underway for another, authorities said early Friday April 19, 2013. Residents of Watertown, a Boston suburb, have been advised to keep their doors locked and not let anyone in.

Police officers stand ready at a crime scene Friday, April 19, 2013, in Watertown, Mass. A tense night of police activity that left a university officer dead on campus just days after the Boston Marathon bombings and amid a hunt for two suspects caused officers to converge on a neighborhood outside Boston, where residents heard gunfire and explosions.

Police investigate along Dexter Avenue in the early morning hours on April 19, 2013 in Watertown, Massachusetts.

A vehicle carrying officers in tactical gear arrives at the Watertown neighborhood of Boston, Friday, April 19, 2013. Reports of explosives being detonated and police are telling reporters to turn off their cell phones. Dozens of officers and National Guard members are in Watertown, where television outlets report that gunfire and explosions have been heard.

Police work a crime scene Friday, April 19, 2013, in Watertown, Mass. A tense night of police activity that left a university officer dead on campus just days after the Boston Marathon bombings and amid a hunt for two suspects caused officers to converge on a neighborhood outside Boston, where residents heard gunfire and explosions.

A police officer checks a driver at a check point as a search for the second of two suspects wanted in the Boston Marathon bombings takes place April 19, 2013 in Watertown, Massachusetts.

Police officers aim their weapons Friday, April 19, 2013, in Watertown, Mass. A tense night of police activity that left a university officer dead on campus just days after the Boston Marathon bombings and amid a hunt for two suspects caused officers to converge on a neighborhood outside Boston, where residents heard gunfire and explosions.

Boston Police mobilize in the parking lot of the Watertown Mall on April 19, 2013 in Watertown, Massachusetts. Earlier, a Massachusetts Institute of Technology campus police officer was shot and killed late Thursday night at the school's campus in Cambridge.

An elderly woman is evacuated from the School and Walnut streets area as police prepare to conduct a massive search for the one remaining suspect on April 19, 2013 in Watertown, Massachusetts.

Police secure a perimeter around an apartment building in a neighborhood in Watertown, Mass., while searching for a suspect in the Boston Marathon bombings, Friday, April 19, 2013.

A police officer in tactical gear conducts a search for Tsarnaev in the Boston Marathon bombings in Watertown, Mass., April 19, 2013.

Police and federal officers drive through a neighborhood while searching for Tsarnaev in Watertown, Mass., April 19, 2013.

Residents watch and wait as police in tactical gear conduct a search for a suspect in the Boston Marathon bombings, April 19, 2013, in Watertown, Mass.

Police walk through a neighborhood in Watertown, Mass., April 19, 2013, while searching for a suspect in the Boston Marathon bombings.

With his weapon drawn, an officer inspects dumpsters behind an apartment building in Watertown, Mass., April 19, 2013.

A police officer enters an apartment building with his dog while searching for a suspect in the Boston Marathon bombings in Watertown, Mass., April 19, 2013.

Police secure a perimeter around an apartment building in a neighborhood in Watertown, Mass., April 19, 2013.

Officials inspect vehicles in Watertown, Mass., April 19, 2013.

Students were evacuated from the U MASS Dartmouth campus on Friday, April 19, 2013 as local and state officials investigate the dorm room of Dzhokhar Tsarnaev.

Police talk to students on the U MASS Dartmouth campus on Friday, April 19, 2013 as local and state officials investigate the dorm room of Dzhokhar Tsarnaev.

Officials search an area on Arsenal Street in Watertown, Mass., Friday, April 19, 2013.

A Massachusetts State Police officer looks through binoculars as UMASS Dartmouth students are evacuated from campus on Friday, April 19, 2013.