Bitcoins could be marked suspicious by the following: "stolen funds (like from a hacking type incident), coming from a dnm, coming from a mixer, coming from terrorist financing, and coming from ransomware payout addresses.”
The following government agencies use Chainalysis "SI, FBI and IRS (they “seem to have the most licenses, or are, at least, the most active in using our software, since their names come up constantly.”) In addition, “ATF, DEA, SEC, Secret Service, CIA (through In Q Tel), and most of the other federal law enforcement agencies are running the software. Only really large police departments are running the software (it isn’t cheap) like NYPD. I know some district attorney offices have software licenses too, but I don’t know which ones. Oh and RCMP uses the software too. And Europol. The national police (NCA) in the UK, as well.”
The use of Mixers.
For privacy, the whistleblower recommends “to avoid mobile wallets, look into Wasabi/Coinjoin and similar efforts, run a VPN/tor at all times”.