BOSTON — Three police officers on Monday described an onslaught of gunfire and bombs thrown during a violent confrontation with the Boston Marathon bombers days after the deadly attack and one suspect’s furious escape in a stolen car that ended with him dragging his brother’s body through the street.

The testimony by Watertown officers came hours after jurors in the federal death penalty trial of Dzhokhar Tsarnaev went to see the bullet-ridden boat he was found hiding in the evening of April 19, 2013.

Earlier that day, shortly after midnight, one officer spotted a carjacked Mercedes SUV on a quiet residential street. That set off a frenzied clash in which Dzhokhar and his older brother, Tamerlan, hurled explosives at police, including two pipe bombs and one pressure-cooker bomb similar to those used near the marathon finish line that killed 3 people and injured more than 260 others, the officers testified.

Joseph Reynolds, the first officer at the scene, said he “locked eyes” with the SUV driver, who was later identified as Tamerlan Tsarnaev. Reynolds said Tamerlan got out of the car and began firing at him.

“All I could see was muzzle flashes,” he said. “I couldn’t count it. It was nonstop.”