Federal authorities have accused four men of distributing synthetic drugs linked to several overdoses and two deaths, including that of a young Minnesota man.

An indictment unsealed this week in Fargo brings charges of conspiracy to distribute controlled substances or analogues of them against Charles W. Carlton, 28, of Katy, Texas; Byron J. Landry, 27, of Kiln, Miss.; John R. Polinski, 25, of Houston, Texas, and Ryan B. Lane, 27, of East Grand Forks, Minn.

The indictment said that Christian Bjerk, 18, of Grand Forks, N.D., and Elijah R. Stai, 17, of Park Rapids, Minn., were killed by overdoses of the psychedelic hallucinogen 2C-I-NBOMe, which authorities said was distributed by the defendants.

Adam T. Budge, 19, of East Grand Forks, has pleaded guilty in Minnesota to giving the drug to Stai, who died a few days short of his 18th birthday.

Authorities say at least five people who overdosed required hospitalization.

According to the indictment:

Carlton, the alleged ringleader, used an online business called Motion Resources to import illegal substances from several countries and distribute them in the United States. Federal authorities are seeking to force him to forfeit $385,000 linked to the operation.

Andrew M. Spofford and William Fox, both of Grand Forks, have pleaded guilty to roles in the conspiracy.

The increasing popularity of synthetic drugs has alarmed authorities, who blame them for thousands of calls to poison control centers and for more than 20 deaths in the United States, including Stai and at least two others in Minnesota.

PAUL WALSH