Rep. Mike Honda (D-San Jose) in a file photo from May 2013.Rep. Mike Honda (D-San Jose) has filed a lawsuit against his opponent, Democrat Ro Khanna, alleging that Khanna's&nbsp;campaign manager illegally obtained sensitive fundraising data and used it to contact Honda's supporters.The lawsuit, filed Thursday morning in the U.S. District Court of Northern California, says&nbsp;Brian Parvizshahi&nbsp;had access to donor lists and other proprietary information in 2012, when he served as an intern for a fundraising consultant working for Honda at the time.After he left the internship, the complaint alleges, Parvizshahi continued to access files related to Honda's fundraising, including after he joined the Khanna campaign in January 2014.Files were accessed repeatedly between February 2013 and June 2015&nbsp;by a Dropbox account and computer bearing Parvizshahi's name, the lawsuit claims.Honda's campaign said&nbsp;it was notified in May by Arum Group, its former fundraising consultant, that Parvizshahi&nbsp;had been inadvertently left on the company's Dropbox access list after leaving his internship. His access was revoked that day, the campaign said.The complaint claims one of the documents Parvizshahi had&nbsp;access to was a list of Honda donors who had contributed more than $1,000,&nbsp;labeled "1,000 Cranes,"&nbsp;which was later leaked to local website&nbsp;San Jose Inside and became the source of an ethics complaint.&nbsp;Some of the donors on that list, Honda's campaign says, received unsolicited emails from Khanna asking to speak with them to discuss his campaign.Honda has remained under the cloud of an ongoing investigation after the Office of Congressional Ethics found "substantial reason to believe"&nbsp;he&nbsp;used taxpayer resources to benefit his campaign.Hari Sevugan, a spokesman for the Khanna campaign, says neither Khanna&nbsp;nor the campaign has been served with the lawsuit."The fact that Mike&nbsp;Honda went to the press before serving us tells you what this is really about:&nbsp;politics," Sevugan said in a statement. "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."Khanna, 39, narrowly bested the veteran congressman, 75, in the June primary, receiving 2,200 more votes in the hotly contested race.At a press conference Thursday, Honda&nbsp;campaign manager Michael Beckendorf&nbsp;likened the alleged breach to a "modern day Watergate" that amounted to a "violation of privacy and harassment" of Honda supporters who apparently landed on Khanna's&nbsp;email lists.Honda's campaign claims having&nbsp;evidence&nbsp;Khanna knew about the breach, including an email exchange with one such Honda supporter in which Khanna personally responded, asking Parvizshahi to remove her from the mailing list."What you have here is a cyberattack," said&nbsp;Gautum Dutta, an attorney for Honda's campaign. "You&nbsp;have the theft of confidential, proprietary information that's then used against the supporters of a rival campaign. That's un-American and it's illegal."Honda spoke with The Times in Washington, D.C. Thursday, saying he'd received many calls from supporters asking why they were getting emails from Khanna's campaign.&nbsp;Honda did not say if the campaign will seek criminal charges against Parvizshahi. "Under the Computer Fraud Abuse Act, there's a great possibility&nbsp;that something went awry, and I think that that's something we need to move forward with," Honda said.The Honda campaign says it is seeking "all available compensatory and injunctive relief" and has asked&nbsp;Khanna's campaign to destroy or return all information it may have obtained.Read the full complaint here.