Mr. Blevins, 45, said there were plenty of families like his still living in Camden, working people with no connections to the drug trade. But even his family has been touched by the violence: In July, his granddaughter’s aunt was shot and killed outside a Camden bar.

Image Raymond Morales, 35, is testifying in federal court. Credit... Jessica Kourkounis for The New York Times

“She was No. 12,” said the granddaughter, Da’Ja Cooksey, 8, as she finished her homework at the dining room table. Da’Ja’s mother, Joya Kilcrest, corrected her: In fact, it was the 14th murder of that year.

“I’ve steered plenty of kids away from drugs,” said Mr. Blevins, who has pulmonary fibrosis and often stays home, wired to an oxygen tank. “And I’ve gone to a lot of funerals.”

Mr. Blevins is one of many people in the city following the trial of Mr. Morales, who pleaded guilty in 2005 to ordering six killings, running a drug operation and tampering with witnesses. In court, he spoke of the magnitude of his decision to cooperate with the authorities, which led to scores of other arrests.

“I broke the code I lived and breathed,” he said.

A cocaine retailer and wholesaler, Mr. Morales explained how he took a great deal of care to maintain his empire.

He met associates in person, always changing the location, and kept his phone conversations short. Twice, cameras that the authorities had trained on Mr. Morales and his associates were disabled, the wires feeding them cut.

He made millions selling cocaine delivered by couriers from Arizona and New York. He could make $1,000 profit on a kilogram of cocaine, he testified, and his corner operation, run by a manager, could gross up to $7,500 a day. All this went to his operating costs: houses for his wife and girlfriends, prostitutes and other, grimmer expenses.