Because of the semi-anonymous nature of Bitcoin, its used in ransomware attacks. Hackers breach networks and hold them hostage until payment is made to them. Hospitals and schools have been victims of these types of attacks. However, unlike cash, which was favored by thieves in the past, Bitcoin always leaves a trail in the blockchain that investigators can follow.
Criminals are also making their progressive development on how to catch up with the security that technology is bringing to the public to secure their wealth and property. But, I am sure that blockchain technology is ready for hackers and on line extortionist, Since it is a systemic technology with tough encryption security, it is somehow tougher to infiltrate, and have precautionary measures in case of breach.