The Federal Criminal Police Office tweeted that the search took place in Heilbronn in southwestern Germany on Sunday, but didn't give further details. Authorities said almost 1,000 people were affected by the data breach.
"In the majority of cases this purely involved contact details such as telephone numbers, postal addresses or email addresses," Interior Ministry spokesman Soeren Schmidt said. "In about 50 to 60 cases considerably more personal data was published that appears to have been stolen beforehand from those affected."
Several politicians' private emails, scanned letters and Facebook messages were published. Authorities were still investigating who was behind the theft and publication of the information, which appeared to include data on members of all parties in parliament except those from the far-right Alternative for Germany party.
Questions have been raised about the way the data breach was handled by Germany's IT security agency, after it emerged that it was made aware weeks before the mass publication on Jan. 3. Interior Minister Horst Seehofer planned to holds a news briefing with the heads of the Federal Office for Information Security, Arne Schoenbohm, and the Federal Criminal Police Office, Holger Muench, in Berlin on Tuesday.