As part of a law enforcement effort named Operation DisrupTor, more than 120 people have been arrested for selling drugs online.
In Southern California, investigators successfully dismantled the drug-trafficking organization known as "Stealthgod."
The crew is accused of using the darknet to make 18,000 sales of methamphetamine and other illegal drugs.
And investigators say those drug deals spanned at least 35 states and numerous countries.
Police seized 120 pounds of methamphetamine, 14 pounds of pills, ecstasy, $1.6 million in cryptocurrency, and five guns, according to a Department of Justice statement.
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Five people living in Southern California were taken into custody.
Meanwhile, Andres Bermudez, 37, of Palmdale is allegedly a main supplier for the organization and is considered a fugitive.
Operation DisrupTor is the largest U.S. operation targeting criminal activity on the darknet, particularly the trafficking of opioids, according to federal authorities.
Investigators say many young addicts are not purchasing from local dealers, rather going online and buying from pushers who hide behind anonymizing software.
The Department of Justice described Operation DisrupTor as being of the highest priority.
"These darknet marketplaces have grown in popularity at an alarming rate and allow drug traffickers can openly advertise and take orders," Deputy Attorney General Jeffery Rosen said at a news conference. "From anywhere in the world, the darknet invites criminals into our homes and provides unlimited access to illegal commerce."
The Drug Enforcement Administration said many such drugs are coming into the U.S. from Mexico.
And the agency has seen an increase in fentanyl-related deaths. According to the DEA, the synthetic opioid is being shipped to the U.S. through the dark web.