The report from the New York City Office of the Chief Medical Examiner did not specify which of the seven bullets caused the death of the teenager, Kimani Gray; that determination awaits further investigation.

One bullet entered his left shoulder in the rear, exiting in the front; two other bullets struck the back of his thighs, one in the left thigh and one in the right. Two bullets struck from the front, hitting his right thigh; one bullet entered his left side, striking his lower rib cage; and the last bullet hit his left lower forearm.

The autopsy did not establish the order in which the bullets struck Mr. Gray, or determine the path of the bullets, which might make it clearer if Mr. Gray had his back to the officers when he was shot, or if he had twisted away after being struck from the front. But the findings alone that several of the bullets entered his back appeared certain to fan the flames of a community already distrustful of the police and increasingly incensed about the shooting of the teenager.

For two consecutive nights, residents in East Flatbush, where Mr. Gray lived and died, marched in protest vigils and questioned the official account of the shooting. The police said that two plainclothes officers, one of them a sergeant, approached Mr. Gray after observing him break away from a group on a darkened street in East Flatbush around 11:30 p.m. on Saturday.

The police said Mr. Gray had adjusted his waistband in a suspicious manner. Witnesses later told police investigators that the officers ordered Mr. Gray to stop. The police said that the teenager pulled a .38-caliber revolver and pointed it at the officers, who then fired 11 shots, killing him. Mr. Gray's revolver had four bullets in its chamber, the police said.

After the first vigil on Monday night, a smaller group of rowdy young men and women broke off and marauded through several local businesses, throwing items at the police and ransacking a Rite Aid drugstore. When a customer in the store intervened, surveillance video showed, he was assaulted by several members of the group. The police said his cellphone was also taken; at least one suspect has been arrested and charged with assault.

Another vigil is scheduled for Wednesday night.