Sort of. If one person has been paid in crypto for a contract killing and other participants either know that they are facilitating the laundering of illegally-obtained money or suspect as such, then they are culpable.

I haven't really been paying much attention to the mixer thing and I'm not an expert, but the gist is that if you build a big cash blender with the explicit purpose of masking the origin of money, then you are very clearly and willfully facilitating money laundering. If you participate in this money blender, then you are probably assisting in money laundering. The whole thing is shady by nature.

The illegal thing is breaking the traversible chain of provenance of funds. All money transmitters by law MUST keep those records as a condition of being licensed to engage in the business of money transferance on the behalf of a third party.

If you came into possession of a money transmission framework, and you ran accounts for someone else without doing KYC, or integrating with OFAC, and were found to have transacted in a way that facilitated illegal activity or sanctions violation, you are now strictly liable for those violations.

If you wish to participate in the act of moving money, you must make law enforcement's job tractable. It is a pre-requisite of the business vertical in the United States.

In brass tacks plain, layman english:

The United States Financial System is a grafted on appendage of Law Enforcement. Every legal department in a financial services company is responsible for setting up a dedicated division responsible for facilitating an integration with Law Enforcement.

Is that clear?

I'm not making any judgements as to whether it should be that way, mind, just telling it how it is.

Mixers were never practically legal in any way shape or form. They just weren't explicitly stated by the name "Mixer" as being illegal by statute or Administrative dicta.

Not a lawyer, just been part of implementing and auditing my fair share of systems.

You're exactly right - tainted, because the contract killer's money becomes clean (laundered) at the expense of the rest of the money.

Now, as to whether everyone who had money in that pool will be found guilty by "Big Bad Government", which I think is what distresses you - the answer is no. There are additional criteria, as the article mentions.

No, it's step one. There are two more steps to take. One more is taken: the conceal step. Now the question, do the others know whether the crypto is from a contract killing. To quote the article:

> Chris and the other participants suspect the possibility that dirty money is entering the jar, but they don't do due diligence, then they could be found guilty of money laundering.

Say, Chris finds themselves in front of judge and jury for money laundering. An expert for the prosecutor might be able to convince the jury the ratio of criminals among crypto mixers users are so high they should have done due diligence. Which, of course, you can't do if the mixer works properly. This convincing will be immensely helped by the OFAC putting mixer addresses on the SDN list.

Thus, the only way to make sure you stay on the straight and narrow is to not use crypto mixers.

No, there were two other criteria listed