A bloody trail from the carjacked car. More blood behind a house in Watertown. Then an unsuspecting home owner who finds a young man inside his winterized boat.

Those were the clues that led law enforcement to find Dzhokhar Tsarnaev, 19, huddled inside a boat behind a house on Franklin Street in the suburb of Boston.

"He didn't go straight to the boat. We found blood in the car he abandoned [earlier in the day]. We found blood inside a house inside the perimenter," Boston Police Commissioner Ed Davis said at a press conference Friday night. "We thought we got the perimeter solid. ... He was behind the house for a little after."

New video released Friday night after Tsarnaev's arrest, which a resident in Watertown apparently shot from a window, captured sounds of numerous gunshots exchanged allegedly between police and the suspect. More video also showed crowds cheering police for making the arrest and chanting "USA! USA!"

They showed the quick change in atmosphere in and around Boston after the second of two brothers suspected in the Boston Marathon bombings Monday afternoon. Jubilation and relief Friday evening replaced anxiety and fear that held the region in check the whole week.

"It seems like many months since Monday, April 15, since the bombing at the Boston Marathon," FBI Agent-in-Charge Richard DesLauriers said at the press conference. "But it's been only five days."

In a later press conference, President Barack Obama lauded the "professionalism and bravery of law enforcement over five days."

Authorities did not give a minute-by-minute account Friday night of how the younger Tsarnaev — whose brother died in a gun battle with police early Friday — ended up in the boat on Franklin Street. But Davis and State Police Col. Timothy Alben said they were confident Tsarnaev never escaped the locked down town of Watertown at any point Friday.

Police went door-to-door all day. But it was a call to Watertown police that ultimately led to the suspect.

"A call came into Watertown Police ... [who] responded to Franklin Street," Davis said. "A man had gone out of his house. ... He walked out and saw blood on a boat in the backyard. He then opened the top on the boat and saw a man covered in blood. He retreated and called us."

Police say an infrared camera mounted on a helicopter helped confirm the suspect's hiding place in the boat.

After securing the perimeter, police tried to persuade the suspect to get out of the boat, said Boston Police Commissioner Ed Davis.

"He was not communicative," Davis said.

Instead, he said, there was an exchange of gunfire , the final volley of one of the biggest manhunts in American history.

A neighbor described how heavily armed police stormed by her window not long after the lockdown was lifted , the rapid gunfire left her huddled on the bathroom floor on top of her young son.

"I was just waiting for bullets to just start flying everywhere," Deanna Finn said.

The Associated Press contributed to this story.