As Boylston Street, the site of last week's deadly Boston Marathon bombings, limped back to normalcy today, new images surfaced online from the night when brothers Tamerlan and Dzhokhar Tsarnaev allegedly opened fire on authorities on a Watertown, Mass., street.

According to Watertown Police Chief Edward Deveau, the final hours of the Boston terror spree - which left four dead and hundreds injured - began when the Tsarnaevs realized they were being followed by a Watertown police officer.

The two allegedly stopped their car to shoot at the officer and heave a pressure cooker bomb at him, Deveau said.

The manhunt, which locked down the city of Boston for nearly 24 hours, ended when Dzhokhar Tsarnaev, the surviving brother, was taken into custody after being found hiding in a boat.

These images were taken by Andrew Kitzenberg with his smartphone as he watched the shootout unfold from his third-floor bedroom window early Friday morning.

"I was in my living room working on my computer when I heard multiple 'pops' coming from outside," Kitzenberg says on his website. "At that point, I had no idea that I was about to become an eye witness to the biggest news story in the country."

The captions and time stamps are Kitzenberg's.

Image credit: Andrew Kitzenberg

"At the bottom of this image is the blast mark from the pressure cooker bomb that exploded in the middle of the street. At the top of the image, the bright light is a bomb detecting robot that was moving toward the blast mark. (Taken at 1:20:10 am)"

Image credit: Andrew Kitzenberg

"This image was taken from the east-facing window. As soon as the black SUV had left the street officers rushed toward the green sedan and the spot of the shooting. As soon as officers got to the vehicle they started alerting all others on scene that there were "IEDs" on the street and for everyone examining the scene to clear the entire street. Also pictured at the bottom of the image is a Watertown Police SUV that had crashed in our driveway at the start of the gunfight and had many of its windows shot out. (Taken 12:57:52AM)"

Image credit: Andrew Kitzenberg

"The red circle highlights where one of the brothers was taken down and still laying in the street. The black SUV proceeded to accelerate towards the officers and drove in between the two cars at the top of the picture. The SUV side swiped both cars taking out doors and windows and ultimately broke through the vehicle barricade and continued driving west on Laurel St. This was the last I saw of the black SUV."

Image credit: Andrew Kitzenberg

"The red circle highlights the pressure cooker bomb that was used just moments after this photo was taken. The use of this explosive created an enormous cloud of smoke that covered the entire street. While the street was still cloudy with smoke one of the brothers started running down the street towards the officers, while still engaging them in gunshots. As he got closer to the officers, within 10 -15 yards of them, he was taken down. From my vantage point I did not see whether he was tackled to the ground or brought down by gunshots."

Image credit: Andrew Kitzenberg

"The bomb squad had finally inspected the entire vehicle and all the backpacks beside it and have cleared the area. (Taken 5:45:25AM)"

ABC News' Martha Raddatz contributed to this story.