I suspect that this has to do with the AlphaBay seizure from earlier this month.
Per the complaint against the admin of AlphaBay (paragraph 5):
5. For transactions leaving the site, AlphaBay provided "tumbling" and "mixing" services [...] [and] also advertised other external mixing and tumbling services to its users."
I don't think I have ever visited AlphaBay, however I would suspect they advertised bitmixer.
The
forfiture complaint claims that Law Enforcement found the admin of AlphaBay because he posted his email address when he first created the site, and also because he reused an alias he used as an admin of AlphaBay on other forums that can be traced back to his email address. However it appears that Law Enforcement was able to locate the AlphaBay servers, and took them down at a specific time so that they could catch the admin of AlphaBay logged into the backend of AlphaBay, see below:
33. On July 5, 2017, [...] Police [...] arrest[ed] [...] Alexandre CAZES [...] [a]t the time of his arrest, law enforcement discovered CAZES' laptop [...] and logged into the server that hosted the AlphaBay website--CAZES was logged in [...] and had accessed the data center hostin the AlphaBay site in order to execute a reboot command after AlphaBay went offline as a result of a law enforcement-created service outage[...]
I suspect that bitmixer is afraid that law enforcement is going to be able to find their servers, seize them and arrest whoever is behind the website. Based on what has been revealed publicly, this is a risk as long as the site remains online, and shortly thereafter. If bitmixer can cease operations without its servers being located, then its operator's risk of arrest, and the risk of it's servers being seized goes to near zero. The ability for bitmixer's owners to cash out their bitcoin holdings becomes much easier with the activation of SegWit, which is all but guaranteed as of not long ago.
I have a couple of suspects as to who might be ultimately behind bitmixer, some who I think have a higher probability than others of being the operator. I am not going to disclose this list, and hopefully my suspicions will never be tested. I applaud you for closing your service instead of pulling an exit scam (as many businesses have in the past). Good luck!