A prosecutor described the shooting death of Sean Bell in simple, stark terms as the trial of three detectives came to a close yesterday.

“We have a situation where armed men confronted a group of civilians,” a Queens assistant district attorney, Charles Testagrossa, said.

The armed men were undercover detectives who failed to adequately identify themselves when approaching a car carrying Bell and two of his friends, prosecutors say. In the next seconds, 50 bullets were loosed on that car, killing Bell and severely injuring the other two.

Bell and his friends “not only had the right to flee,” Mr. Testagrossa said, they had the “right to use deadly force to defend themselves.”

When the shooting is viewed in that framework, Mr. Testagrossa suggested, Bell’s final decisions — to step on the gas, sideswiping a detective and crashing into a police van in the process — made sense.

For much of the seven-week trial, lawyers have focused on the mind-set of the three detectives, particularly that of Gescard Isnora, who first confronted and opened fire on the Nissan Altima bearing Bell. The question that has received perhaps the most attention during the trial has been whether Detective Isnora had good reason to be so fixed in his mistaken belief that a passenger with Bell, Joseph Guzman, had a gun.

Mr. Testagrossa yesterday largely ignored that question during a dramatic summation that lasted three hours. He tried to recast attention away from whatever the detectives may have been thinking to experiences of the three men who came under fire. Throughout the trial, the defense has painted Bell’s companions that night as thugs.

Mr. Testagrossa focused on a seemingly minor detail: that no bullet holes had been found in the back of the passenger’s seat of Bell’s car, where Guzman, shot 16 times that night, had sat. Mr. Testagrossa said the absence of bullet holes in the fabric meant Guzman had been shot repeatedly in the back as he struggled to squirm away.

“You have a man getting shot in the back as he tries to avoid gunfire,” Mr. Testagrossa said. “That is excessive force in anybody’s mind.”

The case is being heard by a judge instead of a jury; a verdict is expected April 25. The judge, Arthur Cooperman, listened to seven hours of closing arguments yesterday with a stern expression that did not change as the day wore on.

A defense lawyer for Detective Isnora, Anthony Ricco, made a gloomy prediction about what would follow after the verdict, regardless of what Judge Cooperman finds.

“I would imagine this court will be vilified one way or the other,” Mr. Ricco said.

Detective Isnora, who fired 11 shots, and another detective, Michael Oliver, who fired 31 shots, both face manslaughter charges that can carry lengthy prison terms. A third detective, Marc Cooper, faces the far lesser charge of reckless endangerment for firing wildly and aimlessly that night. He is not charged with the killing of Bell or the wounding of Guzman or the third man, Trent Benefield.

Lawyers for the defendants spent much of their closing arguments yesterday assailing the credibility of the prosecution’s witnesses. They spent less time than the prosecution reconstructing the shooting of November 25, 2006, which occurred on a street near a topless bar in the Jamaica section of Queens. Bell, who was to be married later that day, had been celebrating with his friends at the bar.

A lawyer for Detective Oliver, James Culleton, called the witnesses, who had included many of Bell’s friends, “a parade of convicted felons, crack dealers, and men who are not strangers to weapons.”

Mr. Culleton read aloud from Mr. Oliver’s grand jury testimony, in which the detective described being sure that Guzman had a gun.

“I didn’t want to die,” Mr. Oliver had said in describing why he kept shooting.

“It’s a sad case,” Mr. Culleton said at one point. “But in reality no crime was committed.”