An anonymous reader writes: Dutch Police is aggressively going after Dark Web vendors using data they collected from the recently seized Hansa Market. According to reports, police is using the Hansa login credentials to authenticate on other Dark Web portals, such as Dream. If vendors reused passwords, police take over the accounts and set up traps or map the sales of illegal products. Other crooks noticed the account hijacks because Dutch Police changed the PGP key for the hijacked accounts with their own, which was accidentally signed with the name "Dutch Police." The second method of operation spotted by the Dark Web community involves so-called "locktime" files that were downloaded from the Hansa Market before Dutch authorities shut it down on July 20. Under normal circumstances a locktime file is a simple log of a vendor's market transaction, containing details about the sold product, the buyer, the time of the sale, the price, and Hansa's signature. The files are used as authentication by vendors to request the release of Bitcoin funds after a sale's conclusion, or if the market was down due to technical reasons. Before the market went down, these locktime files were replaced with Excel files that contained a hidden image that would beacon back to police servers, exposing the vendor's real location. Dutch Police was able to do this because they took over Hansa servers on June 20 and operated the market for one more month, collecting data on vendors.