I read here in the forum, that agencies investigated into transactions and could track all transactions of cryptocurrencies, that claimed to secure privacy like Dash, ZCash, Monero and a currency, I don't remember anymore. But all transactions could be sorted to the owners with the transfered amounts. Only Monero could stand the track. Transactions where trackable but not the amounts. But unfortunately I can't remember anymore, where the thread was placed here in forum and in which context the transactions where tracked. Maybe because of taxations or illegelal activities. The search here didn't help, also not the search on Google. Maybe members here remember.