(AP Photo/Craig Ruttle)

(AP Photo/Matt Rourke)

(AP Photo/Craig Ruttle)

(9:55 p.m. ET): President Obama is expected to speak from the White House soon. The video is streaming below.

Some quotes from Obama: "Our nation is in debt to the people of Boston... [They] responded with resolve and determination." The president included a tribute to Officer Sean Collier, who killed in the line of duty. "Why do young men who grew up and studied here resort to such violence?" The victims and survivors "deserve answers. ... We will investigate any associations that these terrorists might have had. ... What ever they hoped to achieve, they already failed."

(9:35 p.m. ET): Police are updating the media right now. Police Chief Alben: "We have a victory." Police Commissioner Ed Davis says the man who found Tsarnaev in the boat hadn't checked on the boat sooner, because didn't leave his house all day, until the police lock down was lifted. When asked about more suspects, Davis says "The threat has been removed." The suspect is in serious condition. Here is a new (unconfirmed) image of the suspect being arrested.

(9:25 p.m. ET): Residents have poured into the streets in an impromptu celebration:

(9:23 p.m. ET): There are also reports from the nearby town of New Bedford that three people, who are possibly friends of the suspect, were arrested tonight in a related investigation.

(9:20 p.m. ET): WMUR has what is believed to be the first picture of Tsarnaev in the back of an ambulance. A press conference is scheduled for 9:30 p.m. ET.

(9:16 p.m. ET): WCVB TV reports that the suspect has been taken to Mount Auburn Hospital. Chuck Todd of NBC News reports that the President has been informed of the arrest.

(9:00 p.m. ET): Here's a quick rundown of how the final hours of the manhunt went down. Around 7:00 p.m., shortly after the "shelter in place" condition was lifted, police received a call about a boat that was parked in the backyard of a nearby house. (The house was a couple blocks outside of the Watertown lockdown area, and was not part of the police sweep that took place during the day.) The owner of the boat, which was covered by a tarp, noticed a ladder nearby that was not usually there, and when he went to inspect the boat he noticed blood and a body inside and called police.

When police approached the boat a huge volley of gunfire rang out. It was eventually determined that bombing suspect Dzhokhar Tsarnaev was hiding inside the boat and had likely been there most of the day. Fearing that he might have explosives or a can of gas inside the boat, police set up a perimeter and approached cautiously with the hope of taking him alive. Police threw a series of flashbangs into the boat, and eventually called in a hostage negotiator. However, about two hours after the standoff began, the wounded suspect was taken into custody, alive and conscious. He was placed in ambulance and taken to a local hospital.

(8:47 p.m. ET)

Suspect in custody. Officers sweeping the area. Stand by for further info. — Boston Police Dept. (@Boston_Police) April 20, 2013

(8:37 p.m. ET) Tsarnaev is believed to be wounded and bleeding but still alive. Police trying to convince him to surrender peacefully:

BREAKING NEWS: Globe photographer can hear police say, "We know you're in there. Come out on your own terms. Come out with your hands up." — The Boston Globe (@BostonGlobe) April 20, 2013

His deceased brother's wife just released a statement confirming that the suspect had a daughter.