Recently, Lilita Infante of the US Enforcement Administration [DEA] issued a statement concerning the relationship between Bitcoin and illegal activities. He stated that the volume of Bitcoin transactions used for illegal or criminal activities has increased since 2013, but the relationship between its use in criminal activities has fallen to 10% from a 90% inflated, highlighting the speculative market as a dominant asset.  Infante provided the statement in correspondence with the statistics deriving from the cases he managed at the DEA over a period of 5 years. The DEA official is a special agent at the organization and is one of the 10 people in the Cyber Investigative Task Force. In addition, Infante released a statement in an interview at the office stating:
"The volume has grown enormously, the amount of transactions and the value of the dollar has grown enormously over the years in criminal activities, but the ratio has decreased Most transactions are used for price speculation. "
A permanent case for the DEA for years has been the dark web. Dark web operates in particular on cryptocurrencies and is known exclusively for its criminal activities in the trade of goods such as drugs, among other things. Because of the faster, cheaper and more private nature of cryptocurrency transactions, they have also become ubiquitous in cases of illegal cross-border money laundering, according to the DEA agent.
He also added that the authorities are using blockchain technology against these criminals, which makes the whole equation difficult to win for offenders. This is possible because most of the cryptocurrency blockchains [apart from privacy coins such as Monero, Zcash, among others] are public and immutable.
Last year, the underworld abandoned Bitcoin to adopt private currencies, especially Monero, as the main means of settlement. On this, Europol, the law enforcement agency of the European Union wrote in a report:
"… other cryptocurrencies like Monero, Ethereum and Zcash are gaining popularity in the digital underground."
One of the ways to make a currency transaction anonymous is to use the zero-proof protocol that restricts the display of all transactional details, such as the parties involved, addresses and quantity processed.
However, according to Infante, although some of the cryptocurrencies maintain more privacy than Bitcoin, the authorities still have ways to track the traffickers and other parts of the underworld involved in these transactions.