Second, once they identify the perpetrators, law enforcement needs help to catch them. The borderless nature of cybercrime means many attackers are outside the U.S., making it difficult, but not impossible, to bring them to justice. The U.S. made high-profile arrests in cyber cases like the Yahoo hacker extradited from Canada or the Chinese PLA officer arrested in Belgium. Some hackers, like those harbored by nation-states like Russia, China and North Korea, may never be arrested. But hackers travel, and many are just in it for the money. Improving diplomatic efforts and helping other countries get their cyber cops up to speed will help. Tools such as sanctions and restrictions on travel for nation-state supporters may also cause them to think twice about further attacks.