A California man was arrested on Friday for allegedly staging cyberattacks on a California congressional candidate’s website, according to the Justice Department. Arthur Jan Dam, 32, allegedly staged four DDoS attacks against the candidate’s campaign website between April and May 2018, which forced it offline due to “uncharacteristically high internet traffic.” According to the Intercept, Dam’s wife Kelsey O’Hara was ex-Rep. Katie Hill’s fundraiser during the campaign. The attacks were allegedly aimed at one of Hill’s opponents, Democrat Bryan Caforio, who eventually lost to Hill by less than 3,000 votes. Caforio told BuzzFeed News that the incidents should serve as a “somber reminder that Russia is not the only threat to our democracy.”

The attacks caused Caforio’s site to go offline for 21 hours. One attack occurred just before a debate and another on the day of the primary election. According to the criminal complaint, Caforio spent up to $30,000 to resolve the attacks. The Intercept reported that O’Hara later became Hill’s district director and the campaign received a $500 in-kind contribution from Dam in March 2018 for “Graphic design and website security consultation.” The FBI did not uncover any evidence that Dam’s wife or the candidate were involved in the cyberattacks. He faces up to 10 years in prison.