A French national who was serving at times as an administrator and senior moderator on one of the largest dark web criminal marketplaces was sentenced to 20 years in prison today, after previously pleading guilty to conspiracy to possess with the intent to distribute controlled substances and conspiracy to launder money.

Assistant Attorney General Brian A. Benczkowski of the Justice Department’s Criminal Division, U.S. Attorney Ariana Fajardo Orshan for the Southern District of Florida, Special Agent in Charge Adolphus P. Wright of the U.S. Drug Enforcement Administration (DEA) Miami Field Office, Special Agent in Charge Robert F. Lasky of FBI Miami Field Office, and Special Agent in Charge Michael J. De Palma of IRS Criminal Investigation (IRS-CI), made the announcement.

Gal Vallerius, aka “Oxymonster,” 36, pleaded guilty before U.S. District Court Judge Robert N. Scola Jr. in the Southern District of Florida on Aug. 28. Judge Scola sentenced Vallerius to serve 240 months in prison. Vallierius forfeited 99.98947177 bitcoin and 121.94805811 bitcoin cash.

According to the court record, including the agreed upon factual proffer, beginning in or around November 2013 a criminal online marketplace known as Dream Market began operating on the Tor “dark web” network. Dream Market was designed to promote and facilitate the anonymous sale of illegal items. In time, the Dream Market website became one of the largest dark web criminal marketplaces. All of the items and services on Dream Market were offered for sale in exchange for Bitcoin and other peer-to-peer crypto-currencies.

According to the agreed upon factual proffer, Vallerius first participated in the conspiracy by becoming a vendor on Dream Market. As a vendor, he sold Oxycodone and Ritalin under the moniker “Oxymonster.” Shortly thereafter, Dream Market employed the defendant who acted at times as an administrator and senior moderator. In these positions, he played a role supporting the daily illicit transactions between buyers and vendors on Dream Market, such as trafficking in narcotics, and the laundering of illicit proceeds using virtual currencies, Dream Market’s tumblers and the dark web.

This investigation and prosecution was carried out by members of the South Florida High Intensity Drug Trafficking Area (HIDTA) Task Force. The South Florida HIDTA, established in 1990, is made up of federal, state and local law enforcement agencies that, cooperatively, target the region’s drug trafficking and money laundering organizations. The South Florida HIDTA is funded by the Office of National Drug Control Policy which sponsors a variety of initiatives focused on combatting the nation’s illicit drug trafficking threats.

The prosecution is a result of the ongoing efforts by the Organized Crime Drug Enforcement Task Force (OCDETF), a partnership between federal, state, and local law enforcement agencies. The OCDETF mission is to identify, investigate, and prosecute high-level members of drug trafficking enterprises, bringing together the combined expertise and unique abilities of federal, state, and local law enforcement.

The investigation was conducted by DEA Miami Field Office and Paris Country Office, FBI Miami’s Cyber Task Force, IRS-CI Miami Field Office, U.S. Immigration and Customs Enforcement’s Homeland Security Investigations Miami and Atlanta Field Offices, U.S. Customs and Border Protection’s Field Operations Atlanta, U.S. Postal Inspection Service’s Miami Field Office, the Department of Justice’s Office of International Affairs, Europol, Special Operations Division (SOD), Finnish National Police, Finnish International Judicial Administration of the Ministry of Justice, Dutch National Police, French Ministry of Justice and the Direction Interregionale de la Police Judiciaire as well as the U.S. Attorney’s Office for the Northern District of Georgia. The case was prosecuted by Trial Attorney C. Alden Pelker of the Criminal Division’s Computer Crime and Intellectual Property Section (CCIPS) and Assistant U.S. Attorney Juan A. Gonzalez and former Assistant U.S. Attorney Frank R. Maderal of the Southern District of Florida.