In December 2013 Bitcoin was worth US$1,147 (1,055, 758) and the current value is US$238 (158, 216) The value of Bitcoin is dropping, that means, to avoid losing more money crooks are laundering money. Cyber criminals use Bitcoin for the money laundering part and take payment with it, but theyll move it out almost immediately. Most of them wont keep bitcoins, so they just use it as a layer of obfuscation, and move it to a different form of money.”]
Source: http://securityaffairs.co/wordpress/36246/cyber-crime/ransomwarebitcoin-currency-value-drop.html