ROME—Italian police arrested two people for allegedly hacking the email accounts of politicians, entrepreneurs and government officials, including European Central Bank President Mario Draghi.

Italian police on Tuesday arrested Giulio Occhionero, a 45-year-old financial consultant and nuclear engineer, and his 49-year-old sister Francesca Maria Occhionero, both of whom Italian prosecutors accuse of accessing private emails without authorization and stealing classified information.

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