But after the capture, celebratory bells rang from a church tower. Crowds lined the streets into the center of town. Teenagers waved American flags. Every car that drove by honked. Every time an emergency vehicle went by, people cheered loudly.
Lois Johnson, a 49-year-old attorney, had spent the day inside with her son, so when the celebration started they came outside with a container of cookies they had baked and started handing them out.
Liz Rogers, also an attorney, took one of the pieces of yellow police tape and tied it around her neck like a necklace.
"When you see your town invaded like this, it's stunning," said Rogers, 65. "Everyone in Watertown is just so grateful that he's caught and that we're liberated."
The jubilation was widespread. The mayor of Boston, which was largely paralyzed during the manhunt Friday, tweeted, "We got him!" And at the home of the New York Mets, fans leapt to their feet and cheered when the news spread during a game against the Washington Nationals.
Hundreds of people marched down Commonwealth Avenue, chanting "USA" and singing the Red Sox anthem "Sweet Caroline" as they headed toward Boston Common. Police blocked traffic along part of the street to allow for the impromptu parade.
Earlier, the mood was somber. On Boylston Street, three blocks from the site of the marathon explosions on Monday, several dozen people gathered almost in complete silence. Some were crying.
Boston University student Aaron Wengertsman, 19, wrapped himself in an American flag as a silent crowd gathered. He was on the marathon route a mile from the finish line when the bombs exploded.
"I'm glad they caught him alive," he said. "I thought people might be more excited, but it's humbling to see all these people paying their respects."