Dzhokar Tsarnaev is the Boston Marathon bombings suspect that police are looking for in Watertown, several sources told CNN earlier Friday.
Tamerlan Tsarnaev, 26, was the suspect who was killed during a police confrontation overnight, those same sources told CNN.
Police have said that the man identified by the FBI as "Suspect No. 1" in the Boston Marathon bombings was killed in the police confrontation. The man identified by the FBI as "Suspect No. 2" is on the loose, last seen in Watertown, police said.
[Updated 8:52 a.m. ET]
A recap of the developments that began Thursday night:
The violence began late Thursday with the robbery of a convenience store, not long after the FBI released images of two suspects in the Boston Marathon bombings, Massachusetts State Police spokesman Col. Timothy Alben said.
Soon after, in Cambridge, across the Charles River from Boston, a Massachusetts Institute of Technology police officer was fatally shot while he sat in his car, the Suffolk County District Attorney's Office said in statement. Police believe the bombing suspects were responsible for the shooting.
The same two suspects, according to authorities, then hijacked a car at gunpoint in Cambridge. They released the driver a half-hour later at a gas station. As police picked up the chase, the car's occupants threw explosives out the windows and shot at officers, according to the Suffolk County District Attorney's Office.
Officers fired back, wounding one of the men, possibly the person identified by the FBI as "Suspect No. 1." The man died at Beth Israel Hospital. He had bullet wounds and injuries from an explosion, according to officials. The second man apparently escaped.
Richard H. Donohue Jr., 33, a three-year veteran of the transit system police force, was shot and wounded in the incident and taken to a hospital, a transit police spokesman said Friday. The officer's condition was not immediately known.
[Updated 8:44 a.m. ET]
Police activity in Watertown -- where authorities believe they last saw "Suspect No. 2" during a chase overnight -- seems to be picking up, CNN's Deborah Feyerick reports from the community. A helicopter is hovering over a building, and reporters are being asked to move back from where they were.
[Updated 8:30 a.m. ET]
The Federal Aviation Administration has ordered a 3.5-nautical-mile temporary flight restriction over Boston "to provide a safe environment for law enforcement activities." The restriction is from the surface to 3,000 feet, according to the FAA website.
[Updated 8:21 a.m. ET]
"All taxi service in the city of Boston has been suspended pending further notice," Boston police said on its official Twitter account.
This meshes with authorities' request that all of Boston and many of its suburbs stay indoors -- with doors locked -- until further notice. All public transportation in Boston already has been suspended, schools are closed, and Amtrak service from Boston to Providence, Rhode Island, also has been suspended.
[Updated 8:16 a.m. ET]
The Boston-area transit police officer who was shot and wounded overnight is Richard H. Donohue Jr., 33, a three-year veteran of the force, a transit police spokesman said Friday. Donohue was shot during the manhunt for the Boston Marathon bombing suspects.
[Updated 8:14 a.m. ET]
Several sources tell CNN that the dead suspect has been identified as Tamerlan Tsarnaev, 26, and the one still being sought is Dzhokar Tsarnaev, age 19.
[Updated 8:10 a.m. ET]
The suspects involved in the Boston bombings are brothers originally from the Russian Caucasus and had moved to Kazakhstan at a young age before coming to the United States several years ago, according to a source briefed on the investigation, CNN's Deborah Feyerick reported.
The older of the two brothers had the first name Tamerlan, had studied at Bunker Hill Community College, and wanted to become an engineer, the source said. He then took a year off to train as a boxer, according to the source.
The source said that a posting on a social media site in his name included the comments: "I don't have a single American friend. I don't understand them."