The campaign manager for Ro Khanna broke into a private computer system and illegally downloaded lists of the financial contributions and personal information of more than 10,000 supporters of Rep. Mike Honda, the congressman charged Thursday.

A pair of legal actions filed in San Jose federal court accuses Khanna and his campaign manager, Brian Parvizshahi, of violating the federal Computer Fraud and Abuse Act and the federal Economic Espionage Act by taking the confidential information and using it in the campaign to oust Honda from the seat he has held since 2000.

The two men “conspired to intentionally access Mike Honda for Congress’ confidential, proprietary information” that contained “trade secret data regarding past, current and potential donors,”

Statement of on Honda filing a lawsuit:

“We haven’t had a chance to evaluate the Honda campaign’s complaint and haven’t even been served,” Khanna campaign spokesman Hari Sevugan said. “The fact that Mike Honda went to the press before serving us tells you what this is really about — politics. Down in the polls six weeks before an election, it’s clear Mike Honda will do and say anything to hold on to his seat including suing anyone who is on track to defeat him.”

The suit could have serious consequences. Earlier this year, Chris Correa, the former scouting director for baseball’s St. Louis Cardinals, was sentenced to 46 months in federal prison under the computer fraud law for hacking into the Houston Astros’ scouting records.

Criminal charges aren’t the aim of the legal measures, which seek a preliminary injunction against the campaign calling for the immediate return of the campaign finance data and barring any use of Honda’s files.

“Right now our focus is that we want the information returned and we want the Khanna campaign to stop using it,” said Michael Beckendorf, Honda’s campaign manager. “The information was stolen and we want it back.”

The financial documents under question are gold for any campaign.

Just one file contained detailed information on 9,793 people who gave to Honda between 2008 and 2014, including their names, addresses, email addresses and phone numbers along with their occupation, employer, and date and amount of all donations.

Other files included “incredibly detailed” call sheets and notes, memos on Honda events, information on lobbyists who hosted events, notes about efforts to recruit new donors and even Honda’s credit card information.

The names and emails of a campaign’s donors “are the lifeblood of any successful fundraising (and political) campaign,” Beckendorf said in a court document.

Parvizshahi, a 2012 graduate of Cal State Fullerton, is at the center of the controversy. According to court documents, Parvizshahi was hired in May 2012 as an intern for the Arum Group, a Democratic consultant that at the time handled fundraising for Honda.

Parvizshahi was required to sign a confidentiality agreement before he was given access to client information, including what a company official described as “private, highly sensitive contact and donation information about (Honda’s) donors.”

But when Parvizshashi quit a month later, he kept his access to the password-protected digital Dropbox file containing Honda’s records. According to court documents, computer records show that after he was hired in January 2014 as data director for the Khanna campaign, “Defendent Parvizshasi continually accessed the Honda files,” going into them 44 times before his connection was hurriedly removed after the unauthorized incursions were discovered last May.

“We’ve got Brian’s digital fingerprints on those files,” Beckendorf said in an interview.

The first clue that something was wrong came last October, when 16 of Honda’s backers hurriedly called the campaign to say they had received email messages from Khanna asking to chat “about the race and about my policy ideas.” They also included links to unfavorable news stories about Honda.

Khanna’s messages were polite. When one Honda supporter slammed him for running against the congressman, Khanna replied that “I respect your support of Mike Honda. I just honestly believe this district needs a new beginning.”

The concern, though, was that Khanna sent emails to the donors’ personal accounts, which aren’t part of the public information the Federal Election Commission requires from people who donate $200 or more to a campaign. That means they had to come from another source.

Those complaints were just “the tip of the iceberg,” Beckendorf said, who estimated that for every person who called the Honda campaign to complain, another 50 to 100 received the messages, but didn’t call.

“We knew we definitely had an invasion of privacy we had to address,” he said. “We knew (the email addresses) had to have been obtained illegally, but for a while it was an unsolved mystery.”

The troubles got worse last December, when San Jose Inside published online a list of Honda’s “1,000 Cranes,” donors who gave $1,000 and purportedly got special access and treatment from the congressman and his staff. While Honda has denied any wrongdoing, the program is part of an ongoing congressional ethics investigation into Honda and his congressional staff.

The newspaper reported on Dec. 16, 2015, that the list arrived “in an anonymous envelope.” It included the names, nicknames, employer information and personal phone numbers of 281 people who gave at least $1,000 to Honda’s re-election campaigns in 2010 and 2012.

A document reportedly downloaded by Parvizshahi was an exact match to the one posted by San Jose Inside, Beckendorf said.

The security breach was discovered on May 31, when Honda’s current fundraising consultant received a automatic message that one of Honda’s Dropbox files had been modified. With a couple of phone calls, campaign officials discovered that Parvizshahi, now Khanna’s campaign manager, still had access to financial data from the Honda campaign.

“We knew within moments that the files had been accessed and who had done it,” Beckendorf said.

According to court documents, a political opposition researcher quickly determined just how wide-ranging the breach had been, saying in an email that “it looks like everything related to Mike Honda’s fundraising over the last years is in this folder that Brian (Parvizshahi) had access to.”

That’s a huge deal in a contested race where the candidates are forced to raise plenty of campaign cash, typically from a very limited number of donors.

Not all the information in the suit is a plus for Honda’s case. It’s clear from the documents that Parvizshahi didn’t hack into the computer files, but used an access code his former employer had neglected to remove. And while campaign officials argued that their supporters “were harassed and intimidated” when Khanna sent emails to their personal accounts, that’s likely not the first or last spam any of them have received.

In an exchange that will likely be at least mildly embarrassing to the congressman, he says in a deposition that “I abide by a simple rule: As a matter of respect, one should never solicit supporters of my opponent.”

But a document sent to Beckendorf by his outside expert said the files Parvizshahi had access to included, “Detailed call notes on Honda’s calls to previous Ro donors.”

But the suits still link Khanna to the type of ethical lapses — not to mention potentially criminal conduct — that the Fremont attorney has used to attack Honda and make himself the favorite in the race by finishing ahead of his fellow Democrat in the June primary election.

Khanna’s use of the confidential information “has personally embarrassed me and harmed my reputation,” Honda said in a court declaration. “My supporters expect — and deserve, to have their confidentiality and privacy respected.”

John Wildermuth is a San Francisco Chronicle staff writer. Email: Twitter: @jfwildermuth