Federal officials appeared to have tracked the drug ring since the death of Mr. Kroll .

An indictment unsealed this week did not name Mr. Kroll. But an official with knowledge of the case said a drug overdose victim identified as Victim-1 in the document was the tech executive, who was discovered in his Manhattan apartment on December 16.

After Mr. Kroll’s death, the Candyshop changed its phone number, twice, to avoid detection by law enforcement, officials said.

But it did not change its business. Geoffrey S. Berman, the United States attorney in Manhattan, said that although “they realized the potency of the drugs they were distributing and selling, the defendants continued to sell their poison.”

After Mr. Kroll’s death, the New York Police Department linked up with the New York Field Office of Homeland Security Investigations, the Drug Enforcement Administration and the United States attorney’s office in Manhattan, according to a person with knowledge of the investigation.

The leader of the ring, officials said, was Ariel Tavarez , 38, of Pennsylvania, who often acted as the operator, taking orders and arranging couriers . Christian Baez , 33, Luis Meson , 31 , Kevin Grullon , 25 and Joiffrey Urena , 27 — all of Manhattan — worked as the couriers, and Gregoris Martinez , 34, managed the day-to-day drug supply and cash, officials said .

Lawyers for Mr. Baez, Mr. Martinez and Mr. Urena declined to comment. Lawyers for the other men did not respond to messages seeking comment.

As for Mr. Kroll, he had been a fixture in the tech start-up scene.

He rose to prominence as one of the co-founde rs of the popular short-video app, Vine, which was later acquired by Twitter. He later admitted that he was let go from Twitter shortly afterward for “poor management.” He had also been accused of inappropriate behavior in the workplace toward women. He said he had never sexually harassed anyone.