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.
It will be so sad if some will use bitcoin for selfish desires that would destroy other innocent people. Lots of people have been helped through bitcoin. I am hopeful that bitcoin will be for the common good.