WASHINGTON — The FBI arrested a man connected to former Democratic Rep. Katie Hill’s congressional campaign, according to a federal complaint filed in California Wednesday.

Hill, who flipped a Republican-held seat in California two years ago, resigned from Congress last year after nude photos of her were released without her consent. While she was a candidate in 2018, the website of one of her Democratic rivals — Bryan Caforio — was hacked.

According to the complaint, the FBI arrested Arthur Dam, whose wife worked for Hill’s campaign, accusing him of coordinating four DDoS attacks against her opponent. His arrest was first reported by the Intercept. Hill did not immediately respond to BuzzFeed News’s request for comment.

Though the complaint does not name the victim of the cyberattacks, Caforio confirmed to BuzzFeed News that he is the individual identified as "Victim" in the complaint. The description by the FBI also matches reports from 2018 about Caforio’s campaign hack.

According to a Rolling Stone article from September of that year, Caforio’s website crashed four times during the primary, once during a debate and another time just a week before the election. The attacks were DDoS attacks, which direct overwhelming traffic to a website in an effort to crash it. Caforio narrowly lost the primary.

According to the FBI complaint, Dam registered an Amazon Web Services account to coordinate the attacks and registered it under a pseudonym, but used his real name for payment information. The account that Dam used to attack the site was closed the day the Rolling Stone story was published, according to the complaint.



"In May 2019, the Victim provided information to the FBI that as a result of the DDoS attacks, the Victim suffered various harms, including a reduction of in political donations and campaign visibility, and between approximately $27,000 and $30,000 in expenditures and lot time to respond to, investigate, and mitigate the attacks," the complaint filed this week reads.

Caforio told the FBI that he believed the attacks contributed to his election loss by fewer than 3,000 votes. (Caforio came in third in the primary with 21,821 votes. Hill came in second with 24,507.)

"I’m absolutely shocked and saddened to learn today that Katie Hill’s campaign associates hacked my campaign in order to help her advance through the primary," Caforio told BuzzFeed News in a statement. "This should serve as a somber reminder that Russia is not the only threat to our democracy. There are bad actors on all sides who will do anything for their own personal gain, and we need to come together as Americans to defend our country and hold everyone responsible accountable."



The FBI alleged that Dam visited Caforio's website multiple times and researched the candidate, while also searching for terms and equipment related to DDoS attacks.



"Dam was found to be connected to the cyber attacks through subscriber information, IP addresses, geolocation history, and open sources, including through his employer and his wife, K.O., who worked for one of the Victim’s opponents," the complaint reads.

According to The Intercept, Dam is married to Kelsey O’Hara, who fundraised for Hill during her congressional run and worked for Hill after she was elected to Congress. Federal Election Commission records show that Dam performed “graphic design and website security consultation” for Hill’s 2018 campaign, an in-kind contribution that the campaign valued at $500.

The FBI interviewed both Dam and O'Hara at their home in Santa Monica, California, in November 2019, according to the complaint. Dam, who is an engineer, told the FBI that he occasionally used DDoS attacks at work for testing, though his company later told the FBI that they used third parties for that kind of testing were unaware of any internal tests.

The FBI also searched Dam's home and his office in November, according to the complaint.