Investigators are probing whether Iranian hackers are behind the malicious cyber activity this week that targeted water systems in seven states, including Minnesota. If they are found to be the culprits, it would not be the first time Iranian actors have been linked to cyberattacks against the U.S.For more than a decade, Iranian-linked operators have repeatedly hacked accessible American targets. They scan for widespread vulnerabilities and aim to create disruption, intimidate, gain publicity and undermine trust in the American government. But official confirmation can take weeks or months as investigators collect technical evidence. Investigators are also looking into whether the actor could have attempted to appear Iran-based as a way of stirring the pot amid the U.S. war with Iran.Iran has long denied any involvement in cyberattacks.Here are some of the high-profile Iranian-linked cyberattacks in the U.S.:2011-2013: Dozens of U.S. banksSeven Iranians working for companies connected to the Iranian government and Islamic Revolutionary Guard Corps were charged a decade ago with distributed denial-of-service, or DDOS, attacks against 46 financial institutions between 2011 and 2013. The Justice Department said that bank websites were disabled, which meant customers could not access their accounts online. Collectively, the attacks cost customers and the victim banks tens of millions of dollars in remediation costs.