BERLIN (AP) — German lawmakers on Thursday lifted the parliamentary immunity of a leading far-right politician as part of a probe into alleged tax irregularities.

Lawmakers were asked to lift the immunity of Alexander Gauland, the parliamentary co-leader of the Alternative for Germany party, to allow for “search and seizure decisions ordered by a court” to be carried out.

German weekly Der Spiegel reports that prosecutors in Frankfurt are investigating whether Gauland, 78, failed to submit his personal taxes correctly.

Lawmakers also lifted the immunity of a member of Chancellor Angela Merkel's Christian Democrats. The reason for doing so wasn't immediately clear.

The probe against Gauland is separate from an investigation into his fellow Alternative for Germany leader in parliament, Alice Weidel, who is under scrutiny over possible illegal party funding. She denies the allegation.

Gauland was criticized earlier this week for appearing to sleep during a speech given by Israeli President Reuven Rivlin to the German parliament marking 75 years since the liberation of Auschwitz.