Updated Friday, April 19, 10:07 p.m.
The at-large Boston Marathon bombing suspect is alive in custody after about a two-hour standoff outside a home in Watertown, Mass., Boston police said.
The FBI had conducted a massive manhunt on Friday for Dzhokhar Tsarnaev, the second suspect in this week's bombings. His older brother, Tamerlan Tsarnaev, was killed after a violent rampage through the suburbs of Boston earlier in the day.
There are still questions that remain unanswered, but because of professionals "who brought their A-game, we have a suspect in custody tonight," Massachusetts Gov. Deval Patrick said during a press conference on Friday. "It's a night I think we're all going to rest easy."
Less than an hour after authorities said they did not have an "apprehension" of Tsarnaev's whereabouts, shots were fired on Franklin Street in Watertown.
"We're exhausted folks, but we have victory here tonight," said Col. Timothy Alben of the Massachusetts State Police. "But let's not forget those people along the way."
The events unfolded rapidly late Thursday and into Friday night.
Thursday, April 18:
5 p.m. FBI released surveillance photos of the two men suspected of planting two bombs near the finish line of Monday's Boston Marathon.
10:24 p.m. Gunshots were reported near Building 32 at the Massachusetts Institute of Technology (MIT).
10:28 p.m. There was an armed robbery at a 7-Eleven in Cambridge. Brother suspects Tamerlan and Dzhokhar Tsarnaev were not involved.
10:29 p.m. An MIT campus police officer, who was later identified as Sean Collier, 26, of Somerville, was found shot. The two brothers allegedly approached him in his vehicle and fatally shot him in the head. Suspects allegedly stole the officer's cruiser.
10:31 p.m. Police received a call for an armed carjacking of a Mercedes SUV by two males in Cambridge. A victim was allegedly kept in the car with the two suspects for about 30 minutes. The victim was released uninjured at a gas station in Cambridge. Police began a manhunt into Watertown in pursuit of the vehicle.
A short time later, police exchanged gunfire with the brothers in Watertown. A transit officer was injured in the gunfight and taken to the hospital with injuries.
Friday, April 19:
Tamerlan--the man in the black hat from the FBI photos released six hours earlier--ran toward the officers and ultimately fell to the ground. He had an improvised explosive device strapped to his chest. He was transported to Beth Israel Deaconess Medical Center.
1:35 a.m. Tamerlan was pronounced dead at Beth Israel.
2:30 a.m. Dzhokhar--who wore the white hat in the surveillance images from the Marathon--drove the SUV through a line of police officers at the end of the street. He allegedly threw explosives out of the vehicle's window during a chase from Cambridge to Watertown.
4:19 a.m. Police asked everyone in Watertown to stay inside and avoid answering their doors unless it was a police officer.
5:30 a.m. Massachusetts Bay Transit Authority suspended service.
8 a.m. By this time, Massachusetts Gov. Deval Patrick ordered all of Boston--and the surrounding areas of Watertown, Cambridge, Waltham, Newton, Belmont, and Allston-Brighton--to stay inside and lock all doors.
9:30 a.m. No-fly zone issued for the entire Boston area.
Just after 9:30 a.m. an Amtrak train from Boston's South Station to New York's Pennsylvania Station was stopped and surrounded near Connecticut.
Shortly after 9:45 a.m. President Obama and Vice President Biden convened a briefing in the White House Situation Room with the national security team who were previously scheduled to meet.
10 a.m. The National Guard was staged in an area in Watertown with law enforcement.
12:30 p.m. Boston authorities urged the public to continue to stay indoors as police continued to go door-to-door on each street in a Watertown neighborhood. Investigators were working on new leads and hoped to provide an update within the hour.
1:30 p.m. Despite the Boston lockdown, people in offices were not expected to shelter in place throughout the day, said Kurt Schwartz, director of the Massachusetts Emergency Management Agency. He encouraged them to leave their workplaces by car or cab. Taxi service had been restored in Boston.
6:05 p.m. Boston police officers said they did not have an "apprehension" of the suspect. Authorities lifted the stay-indoors request, but urged residents to remain vigilant.
Just before 7 p.m. there were reports of shots fired in Watertown.
For at least the next hour and a half, the FBI, members of the SWAT team, and police officers engaged in a standoff at a home in Watertown after a report that a man had found a trail of blood and a body inside a boat covered with a tarp on Franklin Street.
8:42 p.m. Boston police officials reported they had the suspect alive in custody.
9:32 p.m. Boston authorities addressed the public. Col. Timothy Alben said officials are "grateful" for the outcome of the event.
10:05 p.m. In a speech to the nation, President Obama said the law enforcement "closed an important chapter in this tragedy."