Dzhokhar A. Tsarnaev, 19, pictured on the left and his older brother Tamerlan. Tamerlan was killed Thursday evening/Friday morning during a chase with law enforcement officers.
This combination of undated photos shows Tamerlan Tsarnaev, 26, left, and Dzhokhar Tsarnaev, 19. The FBI says the two brothers and 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 a getaway attempt in a long night of violence that left Tamerlan dead and Dzhokhar still at large on Friday, April 19, 2013. The ethnic Chechen brothers lived in Dagestan, which borders the Chechnya region in southern Russia. They lived near Boston and had been in the U.S. for about a decade, one of their uncles reported said. (AP Photo/The Lowell Sun & Robin Young) (AP Photo/The Lowell Sun & Robin Young)
Ruslan Tsarni, uncle of the Boston Marathon bombing suspect, speaks with the media outside his home in Montgomery Village in Md. Friday, April, 19, 2013. In a passionate plea, Tsarni urged his nephew to turn himself in Friday, saying he had brought shame to the family and the entire Chechen ethnicity. (AP Photo/Jose Luis Magana)
A resident records the scene around Norfolk Street in Cambridge, Mass., Friday, April 19, 2013 as authorities search for Boston Marathon bombing suspect Dzhokhar Tamerlan, 19, after his older brother Tamerlan Tsarnaev was killed in a furious getaway attempt overnight. During the long night of violence, the brothers killed an MIT police officer, severely wounded another lawman and hurled explosives at police in a car chase and gun battle. (AP Photo/Michael Dwyer)
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.(AP Photo/Matt Rourke) (AP2013)
La policía copa una zona de Watertown, un suburbio cercano a Boston, el viernes 19 de abril del 2013 durante la búsqueda de los sospechosos en los atentados de la maratón de Boston. (Foto AP/Julio Cortez)
Police in tactical gear conduct a search for a suspect in the Boston Marathon bombings, Friday, April 19, 2013, in Watertown, Mass. All residents of Boston were ordered to stay in their homes Friday morning as the search for the surviving suspect in the marathon bombings continued after a long night of violence that left another suspect dead. (AP Photo/Matt Rourke) (AP2013)
Police walk through a neighborhood in Watertown, Mass., while searching for a suspect in the Boston Marathon bombings, Friday, April 19, 2013. The bombs that blew up seconds apart near the finish line of the Boston Marathon left the streets spattered with blood and glass, and gaping questions of who chose to attack and why. (AP Photo/Charles Krupa) (AP2013)
Police in tactical gear arrive on an armored police vehicle as they surround an apartment building while looking for a suspect in the Boston Marathon bombings in Watertown, Mass., Friday, April 19, 2013. The bombs that blew up seconds apart near the finish line of the Boston Marathon left the streets spattered with blood and glass, and gaping questions of who chose to attack and why. (AP Photo/Charles Krupa) (AP2013)
Police patrol through a neighborhood in Watertown, Mass., while searching for a suspect in the Boston Marathon bombings, Friday, April 19, 2013. The bombs that blew up seconds apart near the finish line of the Boston Marathon left the streets spattered with blood and glass, and gaping questions of who chose to attack and why. (AP Photo/Charles Krupa) (AP2013)
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.(AP Photo/Matt Rourke) (AP2013)
Police officers 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.(AP Photo/Matt Rourke) (AP2013)
A Police official looks over object that was picked up by a remote control device, left, as they investigate an incident in Friday, April 19, 2013, in Watertown, Mass. in which shots were reported to have been fired. (AP Photo/Craig Ruttle) (AP2013)
A bomb squad truck arrives at an incident Friday, April 19, 2013, in Watertown, Mass. in which shots were reported to have been fired. (AP Photo/Craig Ruttle) (AP2013)
An armored vehicle arrives in Watertown, Mass., early 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. (AP Photo/Julio Cortez) (AP2013)
Officials work a crime scene in Watertown, Mass., 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. (AP Photo/Julio Cortez) (AP2013)
Police surround a home while searching for a suspect in the Boston Marathon bombings in Watertown, Mass., Friday, April 19, 2013. The two suspects in the Boston Marathon bombing killed an MIT police officer and hurled explosives at police in a car chase and gun battle overnight that left one of them dead and his brother on the loose, authorities said Friday. (AP Photo/Charles Krupa)
A neighbor is escorted to safety as police surround a home while searching for a suspect in the Boston Marathon bombings in Watertown, Mass., Friday, April 19, 2013. The two suspects in the Boston Marathon bombing killed an MIT police officer and hurled explosives at police in a car chase and gun battle overnight that left one of them dead and his brother on the loose, authorities said Friday. (AP Photo/Charles Krupa) (AP2013)
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.(AP Photo/Matt Rourke) (THE ASSOCIATED PRESS2013)
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.(AP Photo/Matt Rourke) (AP2013)
Fotografía de un video de vigilancia distribuido vía Twitter el viernes 19 de abril de 2013 por el Departamento de Policía de Boston muestra a un sospechoso del atentado con bombas en el maratón de Boston entrando a un mini supermercado en Watertown, Massachusetts. (Foto AP/Departamento de Policía de Boston)
Police patrol through a neighborhood in Watertown, Mass., while searching for a suspect in the Boston Marathon bombings, Friday, April 19, 2013. All residents of Boston were ordered to stay in their homes Friday morning as the search for the surviving suspect in the marathon bombings continued after a long night of violence that left another suspect dead. (AP Photo/Charles Krupa) (AP2013)
Police surround a home while searching for a suspect in the Boston Marathon bombings in Watertown, Mass., Friday, April 19, 2013. The two suspects in the Boston Marathon bombing killed an MIT police officer and hurled explosives at police in a car chase and gun battle overnight that left one of them dead and his brother on the loose, authorities said Friday. (AP Photo/Charles Krupa) (AP2013)
Officers wearing tactical gear arrive 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. (AP Photo/Julio Cortez) (THE ASSOCIATED PRESS2013)
With his weapon drawn, an official inspects an apartment building in Watertown, Mass., Friday, April 19, 2013. Dozens of officers and National Guard members are in Watertown, where gunfire and explosions were heard early Friday morning. (AP Photo/Julio Cortez) (AP2013)
Police cover as they surround a home while searching for a suspect in the Boston Marathon bombings in Watertown, Mass., Friday, April 19, 2013. The two suspects in the Boston Marathon bombing killed an MIT police officer and hurled explosives at police in a car chase and gun battle overnight that left one of them dead and his brother on the loose, authorities said Friday. (AP Photo/Charles Krupa) (AP2013)
Maret Tsarnaeva, an aunt of the two suspects in the Boston Marathon bombing, holds a reporter's smart phone which displays a scene from the bomb site, as she speaks to journalists in the lobby of her apartment building in Toronto on Friday April 19, 2013. Tamerlan Tsarnaev, a 26-year-old who had been known to the FBI as Suspect No. 1 and was seen in surveillance footage in a black baseball cap, was killed overnight, officials said. His brother, a 19-year-old college student who was dubbed Suspect No. 2 and was seen wearing a white, backward baseball cap in the images from Monday's deadly bombing at the marathon finish line, escaped. (AP Photo/The Canadian Press, Chris Young) (AP2013)
Maret Tsarnaeva, an aunt of the two suspects in the Boston Marathon bombing, speaks to journalists in the lobby of her apartment building in Toronto on Friday April 19, 2013. Tamerlan Tsarnaev, a 26-year-old who had been known to the FBI as Suspect No. 1 and was seen in surveillance footage in a black baseball cap, was killed overnight, officials said. His brother, a 19-year-old college student who was dubbed Suspect No. 2 and was seen wearing a white, backward baseball cap in the images from Monday's deadly bombing at the marathon finish line, escaped. (AP Photo/The Canadian Press, Chris Young) (AP2013)
Heavily armed FBI agents gather next door to 410 Norfolk Street in Cambridge, Mass., Friday, April 19, 2013. 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 a 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. (AP Photo/Michael Dwyer) (AP2013)
This wanted poster was released by the FBI on Friday, April 19, 2013, showing Dzhokhar Tsarnaev, the suspect the FBI orginally called suspect number 2 in the bombings at the Boston Marathon. (AP Photo/FBI) (THE ASSOCIATED PRESS2013)
State police move into UMASS Dartmouth on Friday, April 19, 2013, to investigate the dorm room of Dzhokhar Tsarnaev, 19, one of the two suspects wanted for the Boston Marathon bombing on Monday. Students at UMASS-Dartmouth were evacuated from campus on Friday as local and state officials investigate the dorm room of Dzhokhar Tsarnaev, 19, one of the two suspects wanted for the Boston Marathon bombing on Monday. Dzhokhar Tsarnaev was registered as a student at the University of Massachusetts Dartmouth, the school said. The campus closed down along with colleges around the Boston area. (AP Photo/Standard Times, Peter Pereira) MANDATORY CREDIT (PETER PEREIRA2013)