The FBI and police in several countries have arrested more than 100 people in a global crackdown on computers hackers, CNN reported. The hackers were linked to a malicious software called Blackshades used to hijack computers remotely without a victim's knowledge. The arrests are the result of a years-long investigation targeting one of the most popular tools used by cybercriminals to hijack computers around the world. Criminals have used it for crimes such as extortion and bank fraud, the FBI said.