Helix operated from 2014 to 2017 as a custodial bitcoin mixer linked to Larry Harmon’s darknet search engine, Grams. The pitch was simple: send in BTC, pay a service fee, and receive different coins back so the original on-chain trail would be harder to follow. In court filings, US authorities described that flow as laundering infrastructure for darknet sales, not a neutral privacy tool, and that framing became central to everything that followed.
According to DOJ and FinCEN statements, Helix processed hundreds of thousands of transactions and moved more than $300 million tied in large part to AlphaBay activity. That scale matters because it turned the case into more than a one-off prosecution. Investigators used Helix to establish a template they could later apply in other mixer cases, which is why it still appears in most summaries of the broader crackdown timeline.
Timeline & Background
The timeline is important because agencies did not treat Helix as a sudden enforcement event. They built a record over multiple years, then paired criminal and civil actions at roughly the same time. That one-two structure later showed up again in other high-profile mixer investigations.
- 2014: Harmon launches Helix alongside Grams, marketing the service to users who wanted to break visible links between source and destination coins.
- 2017: After AlphaBay is dismantled, Helix winds down and Harmon shifts attention to Coin Ninja, a wallet and payments project.
- February 2020: DOJ unseals the indictment and alleges Helix handled about 356,000 bitcoin transactions; FinCEN in parallel announces a combined $60 million civil penalty tied to Helix and Coin Ninja.
- August 2021: Harmon pleads guilty to money-laundering conspiracy, and the court orders forfeiture of cryptocurrency, cash, and other property while requiring continued cooperation.
Criminal Charges & Evidence
The criminal case alleged that Harmon operated Helix as an unlicensed money-transmitting business and knowingly helped users move proceeds tied to darknet crime. Prosecutors did not rely on one data point. They combined technical records, platform messaging, and financial movement into a narrative that jurors and regulators could follow without needing deep blockchain expertise.
Key evidence highlighted in public filings included:
- Server logs tying Helix deposit addresses to AlphaBay vendor accounts and to ransomware payouts.
- Marketing copy explicitly offering to route user coins in ways that suggested deliberate evasion of AML controls.
- Exchange-side financial records that gave investigators a fiat off-ramp trail, not just blockchain-only evidence.
FinCEN pointed to its 2019 guidance to argue that custodial mixing businesses were already on notice: if you take control of customer funds, you are expected to register and run a real AML program. In other words, the agency treated this as a compliance failure with clear prior warning, not a gray area discovered after the fact.
FinCEN Penalty & Compliance Lessons
FinCEN's civil action split the penalty into $40 million linked to Helix and $20 million linked to Coin Ninja. The order described missing or inadequate controls across the board: no meaningful suspicious-activity process, weak sanctions controls, and public-facing claims that downplayed legal exposure. That combination made the penalty read less like a paperwork issue and more like a full risk-management breakdown.
The cooperation terms in the consent order also mattered. They signaled that the case was part of a wider investigative pipeline, similar to themes seen later in cases such as Sinbad/Blender. For privacy-tool operators, Helix is still a practical warning that messaging, logs, and operational choices can all become evidence if a service is treated as custodial mixing.
Lessons for privacy builders:
- Marketing language can be fatal. Public promises about cleaning coins or bypassing controls are easy for prosecutors to frame as intent.
- US nexus brings MSB expectations. A custodial mixer model is treated as money transmission, which triggers registration and AML duties.
- Operational data remains discoverable. Years after shutdown, logs and exchange records can still drive cases and support freezes (see the tracker).
Impact on Later Crackdowns
Helix became a reference point for later enforcement against custodial mixers, including actions that followed against services like Bestmixer, ChipMixer, and eXch. Agencies showed they could combine undercover activity, subpoena returns from exchanges, seized infrastructure data, and archived marketing claims into one coherent theory of the case. That blend lowered the barrier for future prosecutions because the evidentiary playbook was already tested.
The case is also regularly cited when regulators discuss unregistered money transmission in crypto. Even when facts differ across defendants, Helix remains the historical example used to explain why authorities believe some mixer operations are not just privacy software but regulated financial services. That is why this case still connects directly to later policy warnings, including the FBI 2024 advisory.
Primary References
- DOJ indictment of Larry Harmon (2020)
- FinCEN civil penalty announcement (2020)
- Infosecurity coverage of Helix
Author
NotATether
Bitcoin privacy researcher and maintainer of BitMixList. Focused on mixer history, enforcement timelines, and practical privacy workflows for users operating in high-friction jurisdictions.
