The operation used intelligence gathered from an encrypted service developed by the FBI and Australian police.
Tal Prihar admitted to taking bitcoin payments from darknet marketplaces in exchange for referral links.
Jeremy Spence bilked his investors out of $5 million, according to a criminal complaint.
FBI lacks a "comprehensive strategy for addressing the cryptocurrency threat in the future," OIG wrote.
The U.S. Department of Justice is trying to seize bitcoin from 155 addresses it alleges were used by Al Qaeda to fund terrorism.
The chemicals, though never delivered, would have been potent enough to kill 300 people, prosecutors say.
OneCoin, an infamous crypto fraud, makes an uncredited cameo in a leaked FBI intelligence bulletin on the money-laundering risks of investment funds.
The US government urged countermeasures to stymie North Korea's billion-dollar cybercrime campaigns.
The FBI is warning that fraudsters are about to unleash a surge of coronavirus cryptocurrency scams.
Rapper Maksim Boiko had claimed bundles of money he posed with in photos came from rental revenue and investments in bitcoin.
Steve Chen agreed to plead guilty to tax evasion and conspiracy to commit wire fraud in connection with the $147 million Gemcoin scheme.
The FBI is emailing victims of the QuadrigaCX cryptocurrency exchange, confirming the federal agency is investigating the circumstances around its collapse.
The U.S. government's charges against Virgil Griffith are overblown, says one attendee of the North Korean conference that led to the ethereum developer's arrest.
The FBI has arrested two individuals on charges of stealing and attempting to steal $550,000 in cryptocurrency by SIM swapping 10 victims.
Christoper Wray said crypto is becoming a "bigger and bigger" issue for the agency in a Senate hearing with Mitt Romney.