From the rooftop in the Gun Hill Houses where his body was found, the towers of Midtown Manhattan appeared distant in the spring haze. Elevated trains rumbled below, drowning out the jangle of circling ice cream trucks.

It took days for officers to attach a name to the body. Fliers appeared with images of his tattoos and a description of his clothing: a Misfits T-shirt and hat, skateboard-style shoes. Mr. Bressette had been arrested in February on heroin possession charges in Massachusetts, the police there said, and was reported missing this month.

No arrest has been made in his killing, nor in that of Jahbar Campbell, 22, who died in late April in a hail of bullets as he ran with two other men from a group of armed pursuers. There were four or five guns in all. The U-Haul truck sped off but came to a stop nearby, on Reeds Mill Lane. “There is some gang nexus in that case,” Inspector Stephenson said of Mr. Campbell’s killing. Specifically, he added, the Slut Gang, a crew based in the Boston Secor Houses, just off Boston Road.

Rivalries between groups of young men spurred a series of shootings on East 215th Street that culminated in the May 11 killing of Quashawn Thomas, 19, whom the police described as an affiliate of the Big Money Bosses, a local crew feuding with a group called the Young Shooter Gang. There had been gunfire twice on the corner that week, residents said, as young men fired wildly around the park.

“The craziness, it’s an everyday thing,” said Tonya Williams, 29, who moved from North Carolina to the block. Leaning out her second-story window to speak to a reporter on the street, Ms. Williams said she kept her 4-year-old daughter safe by staying indoors and planned to move as soon as possible. “Queens or Staten Island, where it’s quieter,” she said.

Nearby, a pair of patrol officers stood sentry on a street corner as both marked and unmarked police cars passed periodically. “It’s a violent neighborhood,” one explained, declining to be identified. “Be safe,” the other cautioned. “It’s almost dark.”