Alexander Gauland at a conference | Jens Schlueter/Getty Image German far-right leader loses immunity over tax evasion allegations Investigators search homes of Alexander Gauland.

The German parliament voted to lift the immunity of Alexander Gauland, co-leader of the far-right Alternative for Germany (AfD) group in the legislature.

Prosecutors in Frankfurt are investigating Gauland over allegations of tax evasion and asked the Bundestag for permission to carry out court-issued "search and confiscation orders," which lawmakers granted on Thursday.

Police and tax investigators searched Gauland's homes in Potsdam and Frankfurt the same day, a spokeswoman for the prosecutor's office told Der Spiegel magazine.

A spokesperson for the AfD's parliamentary group told German newspaper Frankfurter Allgemeine Zeitung (FAZ) that the procedure was "merely an administrative formality" related to a "mistake" in Gauland's tax return.

The allegations against Gauland first emerged in spring last year. FAZ reported on Thursday that Gauland has been accused of two separate counts of tax evasion — concerning his joint tax assessment with his ex-wife and incorrect accounting related to parliamentary allowances — of about €6,000 in total.

In a separate case, the Bundestag on Thursday lifted the immunity of another lawmaker, Karin Strenz of Chancellor Angela Merkel's Christian Democratic Union (CDU). Strenz was fined €20,000 last year for her involvement in an Azerbaijani bribery scandal, with the Bundestag ruling that she had broken parliamentary rules by failing to properly disclose money and gifts she received from pro-Azerbaijan lobbyists.

She was also removed from the CDU's delegation to the Parliamentary Assembly of the Council of Europe but remained an MP.

German media reported that prosecutors are investigating her on suspicion of "bribery and corruption of elected officials" in connection with the Azerbaijan affair. Investigators searched 16 locations in Germany and Belgium, including Strenz's home and Bundestag office.

Strenz was not available for comment on the investigation, German media reported.